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<a href="config_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="log_8hpp.html">flow/log/log.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="preprocessor">#include &quot;<a class="code" href="component__cfg_8hpp.html">flow/log/detail/component_cfg.hpp</a>&quot;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="preprocessor">#include &lt;boost/unordered_map.hpp&gt;</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="preprocessor">#include &lt;atomic&gt;</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="preprocessor">#include &lt;typeinfo&gt;</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="preprocessor">#include &lt;utility&gt;</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span> </div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment">// Macros.</span></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span> </div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="preprocessor">#ifdef FLOW_DOXYGEN_ONLY </span><span class="comment">// Compiler ignores; Doxygen sees.</span><span class="comment"></span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment">/**</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> * Macro (preprocessor symbol) to optionally set (when building Flow and translation units that use flow::log::Config)</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * to override a certain flow::log::Config internal behavior that can affect flow::log::Logger::should_log() perf.</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * Typically there is no need to set this, especially if when calling</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> * flow::log::Config::init_component_to_union_idx_mapping() one always provides arg value</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> * `component_payload_type_info_ptr_is_uniq = false` (safe default).  (Note: It is recommended to in fact set it</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * to `true`.)  So, if relevant, and if your benchmarks show `should_log()` is using significant</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> * processor cycles, it can make sense to experiment by setting this to other values; namely:</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> *</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_ptr_via_tree_map&quot;`</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_ptr_via_s_hash_map&quot;`</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_ptr_via_b_hash_map&quot;`</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_ptr_via_array&quot;`</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_ptr_via_sorted_array&quot;`</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> *</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> * Adventurous types can also implement their own such a template, as long as it implements the semantics of</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> * `&quot;flow::log::Component_payload_type_dict_by_ptr_via_tree_map&quot;`.</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> *</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> * @see flow::log::Config class doc header Performance section for an overall recipe.</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> *</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> * @internal</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> * ### Impl: The chosen default ###</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> * Regarding the default value: Briefly (this requires understanding of Component_payload_type_dict):</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> * All choices are pretty good, as all rely on pointers and not long type names, but reassuringly</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> * `std::unordered_map` (with `boost::unordered_map` very close) tends to be the best or close, though with only</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> * 2 types in the map linear-search array can be marginally better.  (GNU STL used here; LLVM STL might be</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> * different.)</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> */</span><span class="preprocessor"></span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno"><a class="line" href="config_8hpp.html#a4c7537066356b7dcb9b9090fc98a38d2">   59</a></span><span class="preprocessor">#  define FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_PTR value_for_exposition</span><span class="comment"></span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment">/**</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> * Cousin of #FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_PTR, similarly affecting a related behavior.</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> * Again typically there is no need to set this, especially if when calling</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> * flow::log::Config::init_component_to_union_idx_mapping() one always provides arg value</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment"> * `component_payload_type_info_ptr_is_uniq = true`.  Otherwise, and if your benchmarks show `should_log()` is</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"> * using significant processor cycles, it can make sense to experiment by setting this to other values; namely:</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment"> *</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_val_via_tree_map&quot;`</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_val_via_s_hash_map&quot;`</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_val_via_b_hash_map&quot;`</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_val_via_array&quot;`</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment"> *   - `&quot;::flow::log::Component_payload_type_dict_by_val_via_sorted_array&quot;`</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> *</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> * Adventurous types can also implement their own such a template, as long as it implements the semantics of</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> * `&quot;flow::log::Component_payload_type_dict_by_val_via_tree_map&quot;`.</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> *</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> * @see flow::log::Config class doc header Performance section for an overall recipe.</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> *</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> * @internal</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> * ### Impl: The chosen default ###</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> * Regarding the default value: This is the slower lookup type, and may be irrelevant, but within this category we can</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> * still do better or worse.  As noted in flow::log::Config::Component_payload_type_to_cfg_map doc header</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> * by far the worst are the hash-maps; so not that.</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> * As of this writing that leaves sorted-map-based; linear-search array; and binary-search array.</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> * Empirically (presumably due to the &lt;= ~10 # of types in map) the linear-search array is best, though</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> * when closer to 10 types for some hardware binary-search array works best.  They are close, though, and across</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> * different hardware/software settings we&#39;ve tried to run the unit-test benchmark it&#39;s tough to get completely</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> * solid results that would hold for everyone.  (GNU STL used here; LLVM STL might be</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> * different.)</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> */</span><span class="preprocessor"></span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno"><a class="line" href="config_8hpp.html#a432ef317310a3c5e0f691f092e80494f">   90</a></span><span class="preprocessor">#  define FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_VAL value_for_exposition</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="preprocessor">#else </span><span class="comment">// if !defined(FLOW_DOXYGEN_ONLY)</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span> </div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="preprocessor">#  ifndef FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_PTR</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="preprocessor">#    define FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_PTR Component_payload_type_dict_by_ptr_via_s_hash_map</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="preprocessor">#  endif</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="preprocessor">#  ifndef FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_VAL</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="preprocessor">#    define FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_VAL Component_payload_type_dict_by_val_via_array</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="preprocessor">#  endif</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="preprocessor">#endif </span><span class="comment">// if !defined(FLOW_DOXYGEN_ONLY)</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span> </div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1log.html">flow::log</a></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span>{</div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span> </div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment"></span> </div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment">/**</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment"> * Class used to configure the filtering and logging behavior of `Logger`s; its use in your custom `Logger`s is</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"> * optional but encouraged; supports dynamically changing filter settings even while concurrent logging occurs.</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"> *</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment"> * If you are reading this to know how to configure an existing Logger, then you don&#39;t need further background; just</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment"> * see this API to know how to configure such `Logger`s in a uniform way.</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment"> *</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment"> * If you are, instead, reading this when implementing a new custom Logger, then please see implementation</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment"> * recommendations in Logger doc header before continuing here.</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment"> *</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment"> * @todo Class Config doc header is wordy and might be hard to follow; rewrite for clarity/flow/size.</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment"> *</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment"> * ### Synopsis: How do I use it to configure a Logger?  Just tell me! ###</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment"> * Really it&#39;s pretty easy to use it, but it&#39;s much easier to see how it&#39;s done by example rather than a</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment"> * formal-ish description (which is nevertheless below, in the next section of this doc header).</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment"> * To use Config with a `Config`-supporting Logger in your flow::log-using module M:</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment"> *</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment"> *   - Declare the component `enum` inside the module M.  Declare and define the associated index-to-name map for</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment"> *     that `enum`.  While it is possible to manually do this, we provide some tools to utterly minimize the</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"> *     boiler-plate required (which would be considerable otherwise).  The files `config_enum_{start|end}.macros.[hc]pp`</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment"> *     are those tools.</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment"> *     - Start with config_enum_start_hdr.macros.hpp.</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"> *   - In module M, use this new component `enum` (totally separate from any others, such as Flow&#39;s</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment"> *     flow::Flow_log_component) at log call sites.  More precisely, either pass a value to Log_context ctor or</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment"> *     to FLOW_LOG_SET_CONTEXT().</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"> *     - An example is the pervasive logging done by various Flow sub-modules with the exception of flow::log itself</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment"> *       (which ironically doesn&#39;t do all that much logging, chicken/egg).  Look for Log_context and</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment"> *       FLOW_LOG_SET_CONTEXT() mentions.</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment"> *   - Outside module M, in the program which uses module M -- perhaps along with other modules such as Flow itself --</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment"> *     probably around startup, set up your new `Config`.</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment"> *     Call Config::init_component_to_union_idx_mapping() and Config::init_component_names() to register M&#39;s</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment"> *     `enum` -- AND again for every other logging module besides M (such as Flow itself).  Call</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment"> *     Config::configure_default_verbosity() and Config::configure_component_verbosity() (and friend) to configure</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment"> *     verbosity levels.  Finally, create the specific Logger and give it a pointer to this Config.</span></div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="comment"> *     - Examples of this can almost certainly be found in certain test programs outside of Flow code proper.</span></div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment"> *       Again, setting Config and specific `Logger` object&#39;s config shouldn&#39;t be done in libraries/modules but normally</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment"> *       at the program level, such as around `main()`.</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment"> *     - After this, the logging itself can begin (including from multiple threads).  Concurrently with logging --</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment"> *       which will often call output_whether_should_log() and potentially output_component_to_ostream() -- you</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment"> *       may not safely call any of the above `init_*()` or `configure_*()` methods, with the following important</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="comment"> *       exceptions:</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment"> *       - You may call Config::configure_default_verbosity() safely concurrently with logging to dynamically change</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="comment"> *         verbosity setting.</span></div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span><span class="comment"> *       - You may call Config::configure_component_verbosity() or Config::configure_component_verbosity_by_name()</span></div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment"> *         similarly.</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment"> *</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment"> * ### What Config controls and how ###</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment"> * Let&#39;s get into it more formally.</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment"> *</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment"> * Firstly, Config simply stores simple scalars controlling output behavior.  For example, the public</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment"> * member #m_use_human_friendly_time_stamps controls the style of time stamps in the final output.  It&#39;s just</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment"> * a data store for such things.</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment"> *</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment"> * Secondly, Config knows how to *understand* the *component* values supplied at every single log call site in</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment"> * your program.  (This also ties in to the next thing we discuss, verbosity config.)  See Component doc header.</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment"> * Now, here&#39;s how Config understands components.  In your program, you will use various `flow::log`-using libraries</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span><span class="comment"> * or modules -- including (but not necessarily limited to!) Flow itself.  Each module is likely to feature their own</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment"> * component table, in the form of an `enum class`.  For example, Flow itself has `enum class Flow_log_component`</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment"> * (see common.hpp).</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment"> *   - So, suppose there are two modules, M1 and M2 (e.g., M1 might be Flow itself).  Each will define</span></div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment"> *     a component table `enum class`, C1 and C2, respectively.  You are to *register* C1; and separately/similarly C2;</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment"> *     using an init_component_to_union_idx_mapping() for each of C1 and C2.  (All of this applies for any number</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment"> *     of modules and enums, not just two.)</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment"> *   - The Config maintains a single, merged *component union* table, which will (after registration) map</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment"> *     *every* `C1::` enumeration member AND *every* `C2::` member to a distinct *component union index* integer.</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment"> *     (For example, in the init_component_to_union_idx_mapping() call, you can specify that C1&#39;s members will map</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment"> *     to union indices 1000, 1001, ...; and C2&#39;s to 2000, 2001, ....)  These flat union indices between C1 and C2</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment"> *     must never clash.</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment"> *   - The Config also maintains a single, distinct *name* string, for each component.  An optional feature is provided</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment"> *     to auto-prepend a prefix configured for each registered `enum class` (e.g., &quot;C1_&quot; for all `C1::` members,</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment"> *     &quot;C2_&quot; for all `C2::` members).  One provides (for each of C1, C2) this optional prefix and a simple map from</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment"> *     the `enum` members to their distinct string names.  Use init_component_names().</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment"> *   - After registering each of C1 and C2 with init_component_to_union_idx_mapping() and init_component_names(),</span></div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment"> *     in your *program* (e.g., in `main()`) but outside the modules M1 and M2 *themselves*, the Config now has:</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span><span class="comment"> *     - The ability to map an incoming log::Component (as supplied to Logger::do_log()) to its index in the flat</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment"> *       `Config`-internal union of all component `enum` values.</span></div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment"> *     - Having obtained that flat index, quickly obtain its distinct component name.</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment"> *     - Conversely, suppose one passes in a distinct component name.  Config can now quickly map that string to</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment"> *       its flat index in the union table of all component `enum` values.</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment"> *   - The following two features are built on this mapping of multiple individual component tables onto a single</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment"> *     flat &quot;union&quot; table of components built inside the Config; as well as on the aforementioned mapping of</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment"> *     union table index to component name string; and vice versa.</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="comment"> *</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="comment"> * Thirdly, and crucially, the verbosity filtering (Logger::should_log()) for the client Logger is entirely implemented</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment"> * via the output_whether_should_log() output method; so Logger::should_log() can simply forward to that method.  Here</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment"> * is how one configures its behavior in Config.  At construction, or in a subsequent configure_default_verbosity()</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment"> * call, one sets the *default verbosity*, meaning the most-verbose log::Sev that `should_log()` would let through</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment"> * when no per-component verbosity for the log call site&#39;s specified Component is configured.  In addition, assuming</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><span class="comment"> * more fine-grained (per-component) verbosity config is desired, one can call `configure_component_verbosity*()`</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment"> * to set the most-verbose log::Sev for when `should_log()` is passed that specific Component payload.</span></div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment"> *</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment"> * Setting per-component verbosity can be done by its `enum` value.  Or one can use the overload that takes the</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment"> * component&#39;s distinct (among *all* source component `enum` tables registered before) string name; in which case</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment"> * the aforementioned performant name-to-index mapping is used internally to set the proper union component&#39;s verbosity.</span></div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment"> *</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment"> * (Note that order of calls matters: configure_default_verbosity() wipes out effects of any individual, per-component</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="comment"> * `configure_component_verbosity*()` executed prior to it.  It is typical (in a given round of applying config) to</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span><span class="comment"> * first call configure_default_verbosity() and then make 0 or more `configure_component_verbosity*()` calls for various</span></div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span><span class="comment"> * individual components.)</span></div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span><span class="comment"> *</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="comment"> * Fourthly, output_component_to_ostream() is a significant helper for your Logger::do_log() when actually printing</span></div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span><span class="comment"> * the ultimate character representation of the user&#39;s message and metadata.  The metadata (Msg_metadata) includes</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span><span class="comment"> * a Component; that method will output its string representation to the `ostream` given to it.  To do so it will</span></div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment"> * use the aforementioned ability to quickly map the `C1::` or `C2::` member to the flat union index to that index&#39;s</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment"> * distinct name (the same name optionally used to configure verbosity of that component, as explained above).</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment"> *</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment"> * Or one can opt to print the flat numeric index of the component instead; in which case the reverse name-to-union-idx</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment"> * is not needed.</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment"> *</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment"> * ### Performance tips ###</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span><span class="comment"> * log::Config can have a significant effect on performance in high-intensity production applications.  The key</span></div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment"> * thing is to configure your verbosities so that not too many messages per unit time are actually *logged* -- that</span></div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span><span class="comment"> * is, a log call site (e.g., `FLOW_LOG_INFO(...)`) is invoked, *and* the Logger::should_log() filter returns `true`.</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span><span class="comment"> * Logging to an output itself is near-inescapably expensive, so the code and verbosity config should collaborate to</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span><span class="comment"> * avoid it in normal (e.g., not when debugging a problem) production conditions.  See log::Sev doc header for solid</span></div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="comment"> * conventions as to the meanings of the severities.  If you follow those and generally keep verbosity at INFO, then</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="comment"> * mission shall be accomplished.  So let&#39;s assume that&#39;s the case.</span></div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span><span class="comment"> *</span></div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span><span class="comment"> * We have made every effort to optimize Logger::should_log() -- that is to say Config::output_whether_should_log() --</span></div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment"> * to use as few processor cycles as possible.  This is invoked at ~every log call site, including for those that</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment"> * will *not* actually end up logging.  In high-intensity production scenarios you should consider the following</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment"> * tips to &quot;help&quot; `output_whether_should_log()` be cheap.</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment"> *</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment"> * Most importantly, when invoking init_component_to_union_idx_mapping() for a given `Component enum`</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span><span class="comment"> * (including but often not limited to Flow&#39;s own flow::Flow_log_component), maximize efforts to provide</span></div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment"> * the arg value `component_payload_type_info_ptr_is_uniq = true`.  In particular if all relevant code is</span></div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment"> * statically linked (tends to be the case), then you can do this worry-free.  See init_component_to_union_idx_mapping()</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span><span class="comment"> * doc header for details.</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment"> *</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="comment"> * *If* you were able to completely heed that tip, then there are two possibilities.</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment"> *</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment"> *   - Processor-cycle use benchmarks of yours show that log::Config::output_whether_should_log() uses acceptably</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment"> *     few cycles.  Then, you&#39;re done.</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span><span class="comment"> *   - Such benchmarks show that you&#39;d like for it to use even fewer cycles.  In that case there is an additional</span></div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment"> *     knob you can experiment with and re-run the benchmarks you use:</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span><span class="comment"> *     #FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_PTR.  See its doc header.  In short, though, set that</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment"> *     preprocessor symbol in your build (wherever config.hpp is directly or indirectly `#include`d -- or simply</span></div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment"> *     everywhere; it doesn&#39;t hurt); and in your Flow build (use CMake&#39;s knobs to add compiler defines).</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment"> *     As for what to set it to, try each of the (several) values shown in the aforementioned doc header.</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment"> *     It is possible that the sensible default we chose is not the absolute best in your environment.</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment"> *</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="comment"> * Anecdotally, we have seen in a certain production application servicing tons of requests that this topic</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment"> * can e.g. make `output_whether_should_log()` use between ~3% and ~1% of all cycles -- the latter obviously</span></div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment"> * being far preferable.  Worry not: we then further optimized and chose a sensible default, so that you get</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment"> * close to the low end right off the bat, especially if you can guarantee</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment"> * `component_payload_type_info_ptr_is_uniq = true`.  Given that, you can try to squeeze a bit more performance</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment"> * out of it using the aforementioned preprocessor define.</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment"> *</span></div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment"> * *If* you were unable to always have `component_payload_type_info_ptr_is_uniq = true`, then you can</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment"> * get potential perf improvements by similarly messing with #FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_VAL</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment"> * (note: `_VAL`).</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment"> *</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span><span class="comment"> * ### Thread safety ###</span></div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="comment"> * Formally, Config is thread-safe for all operations when concurrent access is to separate `Config`s.</span></div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment"> * There are no `static` data involved.  Formally, Config is generally NOT thread-safe when concurrent read and write</span></div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment"> * access is w/r/t to a single Config; this includes read/write of any public data members and read/write in the form</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="comment"> * `const`/otherwise method calls.  Informally, one could use an outside mutex, including in any Logger</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment"> * implementation that uses `*this`, but we recommend against this for performance reasons; and see below &quot;exception.&quot;</span></div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment"> *</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span><span class="comment"> * Also formally for a given `*this`: The logging phase is assumed to begin after all `init_*()` calls and any</span></div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment"> * initial `configure_*()` calls; at this point output_whether_should_log() and output_component_to_ostream() may be</span></div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment"> * used at will by any thread; but the pre-logging-phase non-`const` calls are no longer allowed.</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span><span class="comment"> *</span></div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span><span class="comment"> * There is an important exception to the assertion that Config `*this` one must NOT call any write methods once</span></div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span><span class="comment"> * the logging phase has begun.  Informally, this exception should make it possible to use Config safely *and yet*</span></div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno">  271</span><span class="comment"> * dynamically allow changes to Config without any expensive outside mutex.  The exception is as follows:</span></div>
<div class="line"><a id="l00272" name="l00272"></a><span class="lineno">  272</span><span class="comment"> *</span></div>
<div class="line"><a id="l00273" name="l00273"></a><span class="lineno">  273</span><span class="comment"> * Assume, as is proper, that you&#39;ve called all needed init_component_to_union_idx_mapping() and init_component_names()</span></div>
<div class="line"><a id="l00274" name="l00274"></a><span class="lineno">  274</span><span class="comment"> * before any concurrent logging and have now started to log -- you are in the logging phase.</span></div>
<div class="line"><a id="l00275" name="l00275"></a><span class="lineno">  275</span><span class="comment"> * Now assume you want to change verbosity settings during this logging-at-large phase;</span></div>
<div class="line"><a id="l00276" name="l00276"></a><span class="lineno">  276</span><span class="comment"> * this is common, for example, when some dynamic config file changes verbosity settings</span></div>
<div class="line"><a id="l00277" name="l00277"></a><span class="lineno">  277</span><span class="comment"> * for your program.  The following is safe: You may call configure_default_verbosity() and/or</span></div>
<div class="line"><a id="l00278" name="l00278"></a><span class="lineno">  278</span><span class="comment"> * `configure_component_verbosity*()` while expecting the changes to take effect promptly in all threads; namely,</span></div>
<div class="line"><a id="l00279" name="l00279"></a><span class="lineno">  279</span><span class="comment"> * output_whether_should_log() will reflect the change there; and output_component_to_ostream() does not care.</span></div>
<div class="line"><a id="l00280" name="l00280"></a><span class="lineno">  280</span><span class="comment"> * Perf-wise, little to nothing is sacrified (internally, a lock-free implementation is used).</span></div>
<div class="line"><a id="l00281" name="l00281"></a><span class="lineno">  281</span><span class="comment"> *</span></div>
<div class="line"><a id="l00282" name="l00282"></a><span class="lineno">  282</span><span class="comment"> * Corner case: It is also safe to call configure_default_verbosity() and/or `configure_component_verbosity*()`</span></div>
<div class="line"><a id="l00283" name="l00283"></a><span class="lineno">  283</span><span class="comment"> * concurrently with themselves.  Naturally, it is a race as to which thread &quot;wins.&quot;  Moreover,</span></div>
<div class="line"><a id="l00284" name="l00284"></a><span class="lineno">  284</span><span class="comment"> * configure_default_verbosity() with `reset == true` is equivalent to removing the verbosity setting for each</span></div>
<div class="line"><a id="l00285" name="l00285"></a><span class="lineno">  285</span><span class="comment"> * individual component; but only each removal itself is atomic, not the overall batch operation; so concurrent</span></div>
<div class="line"><a id="l00286" name="l00286"></a><span class="lineno">  286</span><span class="comment"> * execution with another `configure_*_verbosity()` call may result in an interleaved (but valid) verbosity table.</span></div>
<div class="line"><a id="l00287" name="l00287"></a><span class="lineno">  287</span><span class="comment"> * Informally, we recommend against any design that would allow concurrent `configure_*()` calls on `*this`; it does</span></div>
<div class="line"><a id="l00288" name="l00288"></a><span class="lineno">  288</span><span class="comment"> * not seem wise.  It does however result in well-defined behavior as described.  The real aim, though, is not this</span></div>
<div class="line"><a id="l00289" name="l00289"></a><span class="lineno">  289</span><span class="comment"> * corner case but only the main case of a series of `configure_*()` calls in thread 1, while logging may be going on</span></div>
<div class="line"><a id="l00290" name="l00290"></a><span class="lineno">  290</span><span class="comment"> * in other threads.</span></div>
<div class="line"><a id="l00291" name="l00291"></a><span class="lineno">  291</span><span class="comment"> *</span></div>
<div class="line"><a id="l00292" name="l00292"></a><span class="lineno">  292</span><span class="comment"> * ### Optional: Thread-local verbosity override ###</span></div>
<div class="line"><a id="l00293" name="l00293"></a><span class="lineno">  293</span><span class="comment"> * In a pinch, it may be desirable -- *temporarily* and *in a given thread of execution only* -- to change the</span></div>
<div class="line"><a id="l00294" name="l00294"></a><span class="lineno">  294</span><span class="comment"> * current verbosity config.  To do so in a given scope `{}` simply do this:</span></div>
<div class="line"><a id="l00295" name="l00295"></a><span class="lineno">  295</span><span class="comment"> *</span></div>
<div class="line"><a id="l00296" name="l00296"></a><span class="lineno">  296</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00297" name="l00297"></a><span class="lineno">  297</span><span class="comment"> *   {</span></div>
<div class="line"><a id="l00298" name="l00298"></a><span class="lineno">  298</span><span class="comment"> *     // In this { scope } temporarily let-through only error messages or more severe.</span></div>
<div class="line"><a id="l00299" name="l00299"></a><span class="lineno">  299</span><span class="comment"> *     const auto overrider = flow::log::Config::this_thread_verbosity_override_auto(flow::log::Sev::S_WARNING);</span></div>
<div class="line"><a id="l00300" name="l00300"></a><span class="lineno">  300</span><span class="comment"> *</span></div>
<div class="line"><a id="l00301" name="l00301"></a><span class="lineno">  301</span><span class="comment"> *     // Now let&#39;s create 3,000 threads each of which would normally log a few &quot;starting thread&quot; startup INFO messages!</span></div>
<div class="line"><a id="l00302" name="l00302"></a><span class="lineno">  302</span><span class="comment"> *     m_thread_pool = std::make_unique&lt;flow::async::Cross_thread_task_loop&gt;(get_logger(), &quot;huge_pool&quot;, 3000);</span></div>
<div class="line"><a id="l00303" name="l00303"></a><span class="lineno">  303</span><span class="comment"> *     m_thread_pool-&gt;start();</span></div>
<div class="line"><a id="l00304" name="l00304"></a><span class="lineno">  304</span><span class="comment"> *   } // Previous thread-local verbosity is restored (whether there was one, or none) upon exit from {block}.</span></div>
<div class="line"><a id="l00305" name="l00305"></a><span class="lineno">  305</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00306" name="l00306"></a><span class="lineno">  306</span><span class="comment"> * You may also query the current setting via `*(this_thread_verbosity_override())`.  Direct assignment of a #Sev</span></div>
<div class="line"><a id="l00307" name="l00307"></a><span class="lineno">  307</span><span class="comment"> * to the latter is allowed, but generally it is both safer and easier to use the RAII</span></div>
<div class="line"><a id="l00308" name="l00308"></a><span class="lineno">  308</span><span class="comment"> * pattern via this_thread_verbosity_override_auto() for setting/restoring the override.</span></div>
<div class="line"><a id="l00309" name="l00309"></a><span class="lineno">  309</span><span class="comment"> *</span></div>
<div class="line"><a id="l00310" name="l00310"></a><span class="lineno">  310</span><span class="comment"> * The value Sev::S_END_SENTINEL indicates the thread-local verbosity override is disabled; and is the initial (default)</span></div>
<div class="line"><a id="l00311" name="l00311"></a><span class="lineno">  311</span><span class="comment"> * state in any thread.  However, generally, it is recommended to use the RAII pattern via</span></div>
<div class="line"><a id="l00312" name="l00312"></a><span class="lineno">  312</span><span class="comment"> * this_thread_verbosity_override_auto() instead of direct assignment, for safe and easy save/restore.</span></div>
<div class="line"><a id="l00313" name="l00313"></a><span class="lineno">  313</span><span class="comment"> *</span></div>
<div class="line"><a id="l00314" name="l00314"></a><span class="lineno">  314</span><span class="comment"> * Note there are no thread-safety concerns with this feature, as it is entirely thread-local.</span></div>
<div class="line"><a id="l00315" name="l00315"></a><span class="lineno">  315</span><span class="comment"> */</span></div>
<div class="line"><a id="l00316" name="l00316"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html">  316</a></span><span class="keyword">class </span><a class="code hl_class" href="classflow_1_1log_1_1Config.html">Config</a></div>
<div class="line"><a id="l00317" name="l00317"></a><span class="lineno">  317</span>{</div>
<div class="line"><a id="l00318" name="l00318"></a><span class="lineno">  318</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00319" name="l00319"></a><span class="lineno">  319</span>  <span class="comment">// Types.</span></div>
<div class="line"><a id="l00320" name="l00320"></a><span class="lineno">  320</span><span class="comment"></span> </div>
<div class="line"><a id="l00321" name="l00321"></a><span class="lineno">  321</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00322" name="l00322"></a><span class="lineno">  322</span><span class="comment">   * Unsigned index into the flat union of component tables maintained by a Config, combining potentially multiple</span></div>
<div class="line"><a id="l00323" name="l00323"></a><span class="lineno">  323</span><span class="comment">   * user component `enum` tables.  Also suitable for non-negative offsets against such indices.</span></div>
<div class="line"><a id="l00324" name="l00324"></a><span class="lineno">  324</span><span class="comment">   */</span></div>
<div class="line"><a id="l00325" name="l00325"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">  325</a></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a> = <a class="code hl_typedef" href="classflow_1_1log_1_1Component.html#a287888e2943b312f4febc3e8e130fc80">Component::enum_raw_t</a>;</div>
<div class="line"><a id="l00326" name="l00326"></a><span class="lineno">  326</span> </div>
<div class="line"><a id="l00327" name="l00327"></a><span class="lineno">  327</span>  <span class="comment">// Constants.</span></div>
<div class="line"><a id="l00328" name="l00328"></a><span class="lineno">  328</span><span class="comment"></span> </div>
<div class="line"><a id="l00329" name="l00329"></a><span class="lineno">  329</span><span class="comment">  /// Recommended default/catch-all most-verbose-severity value if no specific config is given.</span></div>
<div class="line"><a id="l00330" name="l00330"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a94e6c81a4e3dd9b41c1b468f7d7c1a90">  330</a></span><span class="comment"></span>  <span class="keyword">static</span> <span class="keyword">const</span> <a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a94e6c81a4e3dd9b41c1b468f7d7c1a90">S_MOST_VERBOSE_SEV_DEFAULT</a>;</div>
<div class="line"><a id="l00331" name="l00331"></a><span class="lineno">  331</span> </div>
<div class="line"><a id="l00332" name="l00332"></a><span class="lineno">  332</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00333" name="l00333"></a><span class="lineno">  333</span><span class="comment"></span> </div>
<div class="line"><a id="l00334" name="l00334"></a><span class="lineno">  334</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00335" name="l00335"></a><span class="lineno">  335</span><span class="comment">   * Constructs a conceptually blank but functional set of Config.  Namely, no component `enum`s are yet registered</span></div>
<div class="line"><a id="l00336" name="l00336"></a><span class="lineno">  336</span><span class="comment">   * (call init_component_to_union_idx_mapping() and init_component_names() to register 0 or more such `enum` tables).</span></div>
<div class="line"><a id="l00337" name="l00337"></a><span class="lineno">  337</span><span class="comment">   * The default verbosity is set to `most_verbose_sev_default`.</span></div>
<div class="line"><a id="l00338" name="l00338"></a><span class="lineno">  338</span><span class="comment">   *</span></div>
<div class="line"><a id="l00339" name="l00339"></a><span class="lineno">  339</span><span class="comment">   * While you can and should register `enum`s after this, if you don&#39;t then the object&#39;s outputs will act as follows:</span></div>
<div class="line"><a id="l00340" name="l00340"></a><span class="lineno">  340</span><span class="comment">   *   - output_whether_should_log() will simply return `true` if and only if `sev` is no more verbose than</span></div>
<div class="line"><a id="l00341" name="l00341"></a><span class="lineno">  341</span><span class="comment">   *     `most_verbose_sev_default` arg to this ctor.  `component` is ignored in the decision.</span></div>
<div class="line"><a id="l00342" name="l00342"></a><span class="lineno">  342</span><span class="comment">   *   - output_component_to_ostream() will print nothing to the `ostream` arg and hence will return `false`.</span></div>
<div class="line"><a id="l00343" name="l00343"></a><span class="lineno">  343</span><span class="comment">   *</span></div>
<div class="line"><a id="l00344" name="l00344"></a><span class="lineno">  344</span><span class="comment">   * Note that -- particularly in a pinch and in simple applications -- this is perfectly reasonable, simple behavior.</span></div>
<div class="line"><a id="l00345" name="l00345"></a><span class="lineno">  345</span><span class="comment">   * One doesn&#39;t always need per-component verbosity configuration abilities; and one definitely doesn&#39;t always need</span></div>
<div class="line"><a id="l00346" name="l00346"></a><span class="lineno">  346</span><span class="comment">   * to print the component name/index in the log output.  But if one does need these things, then you can</span></div>
<div class="line"><a id="l00347" name="l00347"></a><span class="lineno">  347</span><span class="comment">   * register `enum`s as explained in class doc header.</span></div>
<div class="line"><a id="l00348" name="l00348"></a><span class="lineno">  348</span><span class="comment">   *</span></div>
<div class="line"><a id="l00349" name="l00349"></a><span class="lineno">  349</span><span class="comment">   * @param most_verbose_sev_default</span></div>
<div class="line"><a id="l00350" name="l00350"></a><span class="lineno">  350</span><span class="comment">   *        Same as in configure_default_verbosity().</span></div>
<div class="line"><a id="l00351" name="l00351"></a><span class="lineno">  351</span><span class="comment">   */</span></div>
<div class="line"><a id="l00352" name="l00352"></a><span class="lineno">  352</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a20ba1556441155d7086282f76d051f61">Config</a>(<a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> most_verbose_sev_default = <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a94e6c81a4e3dd9b41c1b468f7d7c1a90">S_MOST_VERBOSE_SEV_DEFAULT</a>);</div>
<div class="line"><a id="l00353" name="l00353"></a><span class="lineno">  353</span><span class="comment"></span> </div>
<div class="line"><a id="l00354" name="l00354"></a><span class="lineno">  354</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00355" name="l00355"></a><span class="lineno">  355</span><span class="comment">   * Copy-constructs `*this` to be equal to `src` config object.</span></div>
<div class="line"><a id="l00356" name="l00356"></a><span class="lineno">  356</span><span class="comment">   *</span></div>
<div class="line"><a id="l00357" name="l00357"></a><span class="lineno">  357</span><span class="comment">   * Performance-wise, this will copy internal per-component</span></div>
<div class="line"><a id="l00358" name="l00358"></a><span class="lineno">  358</span><span class="comment">   * tables (in addition to a few scalars).  These tables are conceptually unions of potentially multiple long</span></div>
<div class="line"><a id="l00359" name="l00359"></a><span class="lineno">  359</span><span class="comment">   * `enum`s; so this probably shouldn&#39;t be done often, but typically Config is</span></div>
<div class="line"><a id="l00360" name="l00360"></a><span class="lineno">  360</span><span class="comment">   * constructed at startup or during rare config change events.</span></div>
<div class="line"><a id="l00361" name="l00361"></a><span class="lineno">  361</span><span class="comment">   *</span></div>
<div class="line"><a id="l00362" name="l00362"></a><span class="lineno">  362</span><span class="comment">   * @warning If this copy construction occurs very soon after a configure_default_verbosity() or</span></div>
<div class="line"><a id="l00363" name="l00363"></a><span class="lineno">  363</span><span class="comment">   *          `configure_component_verbosity*()` call in a *different* thread completes, then it is possible</span></div>
<div class="line"><a id="l00364" name="l00364"></a><span class="lineno">  364</span><span class="comment">   *          that call&#39;s effect won&#39;t register in the resulting `*this`.  In the case of</span></div>
<div class="line"><a id="l00365" name="l00365"></a><span class="lineno">  365</span><span class="comment">   *          configure_default_verbosity() with `reset == true` the clearing of the per-component verbosities may</span></div>
<div class="line"><a id="l00366" name="l00366"></a><span class="lineno">  366</span><span class="comment">   *          register only partially in that situation, though `*this` will still be valid.  Since &quot;very soon&quot; cannot</span></div>
<div class="line"><a id="l00367" name="l00367"></a><span class="lineno">  367</span><span class="comment">   *          be formally defined, it is therefore best to make such a copy in the same thread as the last</span></div>
<div class="line"><a id="l00368" name="l00368"></a><span class="lineno">  368</span><span class="comment">   *          verbosity-modifying call on `src`.  (On the other hand, even otherwise results in valid behavior, but</span></div>
<div class="line"><a id="l00369" name="l00369"></a><span class="lineno">  369</span><span class="comment">   *          it may not be quite as deterministic as preferred and clean.)</span></div>
<div class="line"><a id="l00370" name="l00370"></a><span class="lineno">  370</span><span class="comment">   *</span></div>
<div class="line"><a id="l00371" name="l00371"></a><span class="lineno">  371</span><span class="comment">   * @internal</span></div>
<div class="line"><a id="l00372" name="l00372"></a><span class="lineno">  372</span><span class="comment">   * The warning above is due to the subtlety in the Atomic_raw_sev copy ctor doc header.</span></div>
<div class="line"><a id="l00373" name="l00373"></a><span class="lineno">  373</span><span class="comment">   * @endinternal</span></div>
<div class="line"><a id="l00374" name="l00374"></a><span class="lineno">  374</span><span class="comment">   *</span></div>
<div class="line"><a id="l00375" name="l00375"></a><span class="lineno">  375</span><span class="comment">   * @param src</span></div>
<div class="line"><a id="l00376" name="l00376"></a><span class="lineno">  376</span><span class="comment">   *        Source object.</span></div>
<div class="line"><a id="l00377" name="l00377"></a><span class="lineno">  377</span><span class="comment">   */</span></div>
<div class="line"><a id="l00378" name="l00378"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#add2f471079c285065c692b8e796ad787">  378</a></span>  <a class="code hl_function" href="classflow_1_1log_1_1Config.html#add2f471079c285065c692b8e796ad787">Config</a>(<span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1log_1_1Config.html">Config</a>&amp; src);</div>
<div class="line"><a id="l00379" name="l00379"></a><span class="lineno">  379</span><span class="comment"></span> </div>
<div class="line"><a id="l00380" name="l00380"></a><span class="lineno">  380</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00381" name="l00381"></a><span class="lineno">  381</span><span class="comment">   * For now at least there&#39;s no reason for move-construction.</span></div>
<div class="line"><a id="l00382" name="l00382"></a><span class="lineno">  382</span><span class="comment">   * @todo Reconsider providing a Config move constructor.  I just didn&#39;t need to deal with it.</span></div>
<div class="line"><a id="l00383" name="l00383"></a><span class="lineno">  383</span><span class="comment">   */</span></div>
<div class="line"><a id="l00384" name="l00384"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#ab067e9e513530e7484a30f568b1e11d5">  384</a></span>  <a class="code hl_function" href="classflow_1_1log_1_1Config.html#ab067e9e513530e7484a30f568b1e11d5">Config</a>(<a class="code hl_class" href="classflow_1_1log_1_1Config.html">Config</a>&amp;&amp;) = <span class="keyword">delete</span>;</div>
<div class="line"><a id="l00385" name="l00385"></a><span class="lineno">  385</span> </div>
<div class="line"><a id="l00386" name="l00386"></a><span class="lineno">  386</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00387" name="l00387"></a><span class="lineno">  387</span><span class="comment"></span> </div>
<div class="line"><a id="l00388" name="l00388"></a><span class="lineno">  388</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00389" name="l00389"></a><span class="lineno">  389</span><span class="comment">   * For now at least there&#39;s no reason for copy assignment.</span></div>
<div class="line"><a id="l00390" name="l00390"></a><span class="lineno">  390</span><span class="comment">   * @todo Reconsider providing a Config copy assignment.  I just didn&#39;t need to deal with it.</span></div>
<div class="line"><a id="l00391" name="l00391"></a><span class="lineno">  391</span><span class="comment">   */</span></div>
<div class="line"><a id="l00392" name="l00392"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a60c9a16ebb764e4fcc4208a55c2e785d">  392</a></span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a60c9a16ebb764e4fcc4208a55c2e785d">operator=</a>(<span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1log_1_1Config.html">Config</a>&amp;) = <span class="keyword">delete</span>;</div>
<div class="line"><a id="l00393" name="l00393"></a><span class="lineno">  393</span><span class="comment"></span> </div>
<div class="line"><a id="l00394" name="l00394"></a><span class="lineno">  394</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00395" name="l00395"></a><span class="lineno">  395</span><span class="comment">   * For now at least there&#39;s no reason for move assignment.</span></div>
<div class="line"><a id="l00396" name="l00396"></a><span class="lineno">  396</span><span class="comment">   * @todo Reconsider providing a Config move assignment.  I just didn&#39;t need to deal with it.</span></div>
<div class="line"><a id="l00397" name="l00397"></a><span class="lineno">  397</span><span class="comment">   */</span></div>
<div class="line"><a id="l00398" name="l00398"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#ac8a787b8026d84814bf4edcc91432447">  398</a></span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#ac8a787b8026d84814bf4edcc91432447">operator=</a>(<a class="code hl_class" href="classflow_1_1log_1_1Config.html">Config</a>&amp;&amp;) = <span class="keyword">delete</span>;</div>
<div class="line"><a id="l00399" name="l00399"></a><span class="lineno">  399</span><span class="comment"></span> </div>
<div class="line"><a id="l00400" name="l00400"></a><span class="lineno">  400</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00401" name="l00401"></a><span class="lineno">  401</span><span class="comment">   * A key output of Config, this computes the verbosity-filtering answer to Logger::should_log() based on the</span></div>
<div class="line"><a id="l00402" name="l00402"></a><span class="lineno">  402</span><span class="comment">   * given log-call-site severity and component and the verbosity configuration in this Config, including</span></div>
<div class="line"><a id="l00403" name="l00403"></a><span class="lineno">  403</span><span class="comment">   * the value at `*(this_thread_verbosity_override())`, the value from configure_default_verbosity(),</span></div>
<div class="line"><a id="l00404" name="l00404"></a><span class="lineno">  404</span><span class="comment">   * and the config from `configure_component_verbosity*()`.</span></div>
<div class="line"><a id="l00405" name="l00405"></a><span class="lineno">  405</span><span class="comment">   *</span></div>
<div class="line"><a id="l00406" name="l00406"></a><span class="lineno">  406</span><span class="comment">   * Call this only after the full round of construction, init_component_to_union_idx_mapping(), and (initial)</span></div>
<div class="line"><a id="l00407" name="l00407"></a><span class="lineno">  407</span><span class="comment">   * `configure_..._verbosity()`.  In addition, it is specifically safe to concurrently set verbosity</span></div>
<div class="line"><a id="l00408" name="l00408"></a><span class="lineno">  408</span><span class="comment">   * via configure_default_verbosity() and/or `configure_component_verbosity*()`.</span></div>
<div class="line"><a id="l00409" name="l00409"></a><span class="lineno">  409</span><span class="comment">   *</span></div>
<div class="line"><a id="l00410" name="l00410"></a><span class="lineno">  410</span><span class="comment">   * ### Thread safety on `*this` ###</span></div>
<div class="line"><a id="l00411" name="l00411"></a><span class="lineno">  411</span><span class="comment">   * The last sentence means it&#39;s possible to change verbosities even while logging (which invokes us), as long</span></div>
<div class="line"><a id="l00412" name="l00412"></a><span class="lineno">  412</span><span class="comment">   * as the `init_*()` stuff has all been completed.  For formal details see notes on thread safety in class Config</span></div>
<div class="line"><a id="l00413" name="l00413"></a><span class="lineno">  413</span><span class="comment">   * doc header.</span></div>
<div class="line"><a id="l00414" name="l00414"></a><span class="lineno">  414</span><span class="comment">   *</span></div>
<div class="line"><a id="l00415" name="l00415"></a><span class="lineno">  415</span><span class="comment">   * ### Algorithm for computing return value ###</span></div>
<div class="line"><a id="l00416" name="l00416"></a><span class="lineno">  416</span><span class="comment">   * It&#39;s a matter of comparing `sev` to `S`, where `S` is the applicable log::Sev verbosity setting.</span></div>
<div class="line"><a id="l00417" name="l00417"></a><span class="lineno">  417</span><span class="comment">   * Return `true` if and only if `sev &lt;= S`.</span></div>
<div class="line"><a id="l00418" name="l00418"></a><span class="lineno">  418</span><span class="comment">   *</span></div>
<div class="line"><a id="l00419" name="l00419"></a><span class="lineno">  419</span><span class="comment">   * What is `S`?  It is the first available value of the following three bits of config:</span></div>
<div class="line"><a id="l00420" name="l00420"></a><span class="lineno">  420</span><span class="comment">   *   -# `S = *(this_thread_verbosity_override())`...</span></div>
<div class="line"><a id="l00421" name="l00421"></a><span class="lineno">  421</span><span class="comment">   *      - ...unless it&#39;s Sev::S_END_SENTINEL (disabled, which is default); then:</span></div>
<div class="line"><a id="l00422" name="l00422"></a><span class="lineno">  422</span><span class="comment">   *   -# `S` = the verbosity configured via `configure_component_verbosity*()` for `component`.</span></div>
<div class="line"><a id="l00423" name="l00423"></a><span class="lineno">  423</span><span class="comment">   *      - ...unless no such per-component verbosity was set; then:</span></div>
<div class="line"><a id="l00424" name="l00424"></a><span class="lineno">  424</span><span class="comment">   *   -# `S` = the value given to configure_component_verbosity() or ctor, whichever happened later.</span></div>
<div class="line"><a id="l00425" name="l00425"></a><span class="lineno">  425</span><span class="comment">   *      - This is always available.</span></div>
<div class="line"><a id="l00426" name="l00426"></a><span class="lineno">  426</span><span class="comment">   *</span></div>
<div class="line"><a id="l00427" name="l00427"></a><span class="lineno">  427</span><span class="comment">   * @see this_thread_verbosity_override() and this_thread_verbosity_override_auto().</span></div>
<div class="line"><a id="l00428" name="l00428"></a><span class="lineno">  428</span><span class="comment">   * @see configure_default_verbosity() and Config().</span></div>
<div class="line"><a id="l00429" name="l00429"></a><span class="lineno">  429</span><span class="comment">   * @see configure_component_verbosity() and configure_component_verbosity_by_name().</span></div>
<div class="line"><a id="l00430" name="l00430"></a><span class="lineno">  430</span><span class="comment">   *</span></div>
<div class="line"><a id="l00431" name="l00431"></a><span class="lineno">  431</span><span class="comment">   * @param sev</span></div>
<div class="line"><a id="l00432" name="l00432"></a><span class="lineno">  432</span><span class="comment">   *        See Logger::should_log().</span></div>
<div class="line"><a id="l00433" name="l00433"></a><span class="lineno">  433</span><span class="comment">   * @param component</span></div>
<div class="line"><a id="l00434" name="l00434"></a><span class="lineno">  434</span><span class="comment">   *        See Logger::should_log().</span></div>
<div class="line"><a id="l00435" name="l00435"></a><span class="lineno">  435</span><span class="comment">   * @return `true` if we recommend to let the associated message be logged; `false` to suppress it.</span></div>
<div class="line"><a id="l00436" name="l00436"></a><span class="lineno">  436</span><span class="comment">   */</span></div>
<div class="line"><a id="l00437" name="l00437"></a><span class="lineno">  437</span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#ae429a329e31a41ba75f94578b0e7f26c">output_whether_should_log</a>(<a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> sev, <span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1log_1_1Component.html">Component</a>&amp; component) <span class="keyword">const</span>;</div>
<div class="line"><a id="l00438" name="l00438"></a><span class="lineno">  438</span><span class="comment"></span> </div>
<div class="line"><a id="l00439" name="l00439"></a><span class="lineno">  439</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00440" name="l00440"></a><span class="lineno">  440</span><span class="comment">   * An output of Config, this writes a string representation of the given component value to the given `ostream`,</span></div>
<div class="line"><a id="l00441" name="l00441"></a><span class="lineno">  441</span><span class="comment">   * if possible.  Returns `true` if it wrote anything, `false` otherwise.</span></div>
<div class="line"><a id="l00442" name="l00442"></a><span class="lineno">  442</span><span class="comment">   * Call this only after the full round of construction, init_component_to_union_idx_mapping(), and</span></div>
<div class="line"><a id="l00443" name="l00443"></a><span class="lineno">  443</span><span class="comment">   * init_component_names().</span></div>
<div class="line"><a id="l00444" name="l00444"></a><span class="lineno">  444</span><span class="comment">   *</span></div>
<div class="line"><a id="l00445" name="l00445"></a><span class="lineno">  445</span><span class="comment">   * If the component&#39;s type (`component.payload_type()`) has not been properly registered via</span></div>
<div class="line"><a id="l00446" name="l00446"></a><span class="lineno">  446</span><span class="comment">   * init_component_to_union_idx_mapping(), it returns `false` and writes nothing.  Otherwise, if no name was registered</span></div>
<div class="line"><a id="l00447" name="l00447"></a><span class="lineno">  447</span><span class="comment">   * (either because it wasn&#39;t included in a init_component_names() call, or because in that call</span></div>
<div class="line"><a id="l00448" name="l00448"></a><span class="lineno">  448</span><span class="comment">   * `output_components_numerically == true`), it will output the component&#39;s numeric index in the flat union table;</span></div>
<div class="line"><a id="l00449" name="l00449"></a><span class="lineno">  449</span><span class="comment">   * and return `true`.  Finally, if a name is indeed registered, it will output that string (details</span></div>
<div class="line"><a id="l00450" name="l00450"></a><span class="lineno">  450</span><span class="comment">   * in init_component_names() doc header) and also return `true`.</span></div>
<div class="line"><a id="l00451" name="l00451"></a><span class="lineno">  451</span><span class="comment">   *</span></div>
<div class="line"><a id="l00452" name="l00452"></a><span class="lineno">  452</span><span class="comment">   * @param os</span></div>
<div class="line"><a id="l00453" name="l00453"></a><span class="lineno">  453</span><span class="comment">   *        Pointer (not null) to the `ostream` to which to possibly write.</span></div>
<div class="line"><a id="l00454" name="l00454"></a><span class="lineno">  454</span><span class="comment">   * @param component</span></div>
<div class="line"><a id="l00455" name="l00455"></a><span class="lineno">  455</span><span class="comment">   *        The component value from the log call site.  `component.empty()` (no component) is allowed.</span></div>
<div class="line"><a id="l00456" name="l00456"></a><span class="lineno">  456</span><span class="comment">   * @return `true` if 1 or more characters have been written to `*os`; else `false`.</span></div>
<div class="line"><a id="l00457" name="l00457"></a><span class="lineno">  457</span><span class="comment">   */</span></div>
<div class="line"><a id="l00458" name="l00458"></a><span class="lineno">  458</span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a6376bf2af57f655c1cdf00791e6a2f7f">output_component_to_ostream</a>(std::ostream* os, <span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1log_1_1Component.html">Component</a>&amp; component) <span class="keyword">const</span>;</div>
<div class="line"><a id="l00459" name="l00459"></a><span class="lineno">  459</span><span class="comment"></span> </div>
<div class="line"><a id="l00460" name="l00460"></a><span class="lineno">  460</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00461" name="l00461"></a><span class="lineno">  461</span><span class="comment">   * Registers a generically-typed `enum class` that represents the full set of the calling module&#39;s possible</span></div>
<div class="line"><a id="l00462" name="l00462"></a><span class="lineno">  462</span><span class="comment">   * component values that it will supply at subsequent log call sites from that module.  The caller supplies:</span></div>
<div class="line"><a id="l00463" name="l00463"></a><span class="lineno">  463</span><span class="comment">   *   - The template argument `Component_payload`, which is an `enum` and is thus castable to the unsigned</span></div>
<div class="line"><a id="l00464" name="l00464"></a><span class="lineno">  464</span><span class="comment">   *     integer type `component_union_idx_t`.</span></div>
<div class="line"><a id="l00465" name="l00465"></a><span class="lineno">  465</span><span class="comment">   *   - The signed integer that shall be *added* to any log-call-site-supplied `enum` value in order to yield the</span></div>
<div class="line"><a id="l00466" name="l00466"></a><span class="lineno">  466</span><span class="comment">   *     flat-union index in `*this` merged table of all component `enum`s.  For example, if we assume that no module</span></div>
<div class="line"><a id="l00467" name="l00467"></a><span class="lineno">  467</span><span class="comment">   *     will ever exceed 1,000 components in its `enum`, then module 1 can register its `enum` C1 with</span></div>
<div class="line"><a id="l00468" name="l00468"></a><span class="lineno">  468</span><span class="comment">   *     `enum_to_num_offset` 1,000, module 2 with 2,000, module 3 with 3,000, etc.  Then the various C1 `enum` values</span></div>
<div class="line"><a id="l00469" name="l00469"></a><span class="lineno">  469</span><span class="comment">   *     0, 1, ... will map to merged 1,000, 1,001, ...; C2&#39;s 0, 1, ... to 2,000, 2,001, ...; etc.</span></div>
<div class="line"><a id="l00470" name="l00470"></a><span class="lineno">  470</span><span class="comment">   *     - This can be negative, because why not?  Be careful.</span></div>
<div class="line"><a id="l00471" name="l00471"></a><span class="lineno">  471</span><span class="comment">   *   - The &quot;sparse size&quot; of the `enum`.  Details are below.</span></div>
<div class="line"><a id="l00472" name="l00472"></a><span class="lineno">  472</span><span class="comment">   *</span></div>
<div class="line"><a id="l00473" name="l00473"></a><span class="lineno">  473</span><span class="comment">   * @note If this is not acceptable -- maybe you want to pack them more tightly, or you have some other clever mapping</span></div>
<div class="line"><a id="l00474" name="l00474"></a><span class="lineno">  474</span><span class="comment">   *       in mind -- then Config might require a new feature (likely an overload of this method) which lets one simply</span></div>
<div class="line"><a id="l00475" name="l00475"></a><span class="lineno">  475</span><span class="comment">   *       provide the mapping in function (callback) form.  In fact, in a previous version of Flow, this was provided;</span></div>
<div class="line"><a id="l00476" name="l00476"></a><span class="lineno">  476</span><span class="comment">   *       and in fact the present overload merely wrapped that more-general overload.</span></div>
<div class="line"><a id="l00477" name="l00477"></a><span class="lineno">  477</span><span class="comment">   *       We removed this primarily for perf reasons: Always using this numeric-offset technique allowed for an inlined</span></div>
<div class="line"><a id="l00478" name="l00478"></a><span class="lineno">  478</span><span class="comment">   *       implementation in the very-frequently-called (at every log call site) output_whether_should_log().  It would</span></div>
<div class="line"><a id="l00479" name="l00479"></a><span class="lineno">  479</span><span class="comment">   *       be possible to add it back in while *also* optimizing for the expected-to-be-used-typically offset technique,</span></div>
<div class="line"><a id="l00480" name="l00480"></a><span class="lineno">  480</span><span class="comment">   *       thus having essentially the best of both worlds (perf when possible, flexibility when necessary).  However,</span></div>
<div class="line"><a id="l00481" name="l00481"></a><span class="lineno">  481</span><span class="comment">   *       since the &quot;flexible&quot; API appears unlikely to be needed, we decided it&#39;s over-engineering to keep it in --</span></div>
<div class="line"><a id="l00482" name="l00482"></a><span class="lineno">  482</span><span class="comment">   *       unless the need does appear in the future.  In that case it should be possible to look in source control</span></div>
<div class="line"><a id="l00483" name="l00483"></a><span class="lineno">  483</span><span class="comment">   *       history and bring back its core elements (without removing the inlined offset-technique code path).  At this</span></div>
<div class="line"><a id="l00484" name="l00484"></a><span class="lineno">  484</span><span class="comment">   *       stage this is not a formal to-do -- more of a note for posterity.</span></div>
<div class="line"><a id="l00485" name="l00485"></a><span class="lineno">  485</span><span class="comment">   *</span></div>
<div class="line"><a id="l00486" name="l00486"></a><span class="lineno">  486</span><span class="comment">   * Behavior is undefined if an index collision occurs here or in a subsequent `init_*()` or other relevant call.</span></div>
<div class="line"><a id="l00487" name="l00487"></a><span class="lineno">  487</span><span class="comment">   * In particular take care to provide sufficient slack space (e.g., if you use `enum_to_num_offset` which are</span></div>
<div class="line"><a id="l00488" name="l00488"></a><span class="lineno">  488</span><span class="comment">   * multiples of 5, then a collision will probably occur at some point).</span></div>
<div class="line"><a id="l00489" name="l00489"></a><span class="lineno">  489</span><span class="comment">   *</span></div>
<div class="line"><a id="l00490" name="l00490"></a><span class="lineno">  490</span><span class="comment">   * If one has called `init_component_to_union_idx_mapping&lt;T&gt;()` with the same `T` in the past, then behavior</span></div>
<div class="line"><a id="l00491" name="l00491"></a><span class="lineno">  491</span><span class="comment">   * is undefined, so don&#39;t.  (Informally, depending on whether/how one has called init_component_names() and</span></div>
<div class="line"><a id="l00492" name="l00492"></a><span class="lineno">  492</span><span class="comment">   * `configure_component_verbosity*()`, this can actually be done safely and with well-defined results.  However,</span></div>
<div class="line"><a id="l00493" name="l00493"></a><span class="lineno">  493</span><span class="comment">   * I did not want to go down that rabbit hole.  If it becomes practically necessary, which I doubt, we can revisit.</span></div>
<div class="line"><a id="l00494" name="l00494"></a><span class="lineno">  494</span><span class="comment">   * This is not a formal to-do as of this writing.)</span></div>
<div class="line"><a id="l00495" name="l00495"></a><span class="lineno">  495</span><span class="comment">   *</span></div>
<div class="line"><a id="l00496" name="l00496"></a><span class="lineno">  496</span><span class="comment">   * ### Important: Performance and `component_payload_type_info_ptr_is_uniq` ###</span></div>
<div class="line"><a id="l00497" name="l00497"></a><span class="lineno">  497</span><span class="comment">   * Call this flag arg `F` for brevity; and let `T = typeid(Component_payload)` (the RTTI type in that template</span></div>
<div class="line"><a id="l00498" name="l00498"></a><span class="lineno">  498</span><span class="comment">   * arg).  Formally: If and only if `F == true`, you guarantee that subsequently any call</span></div>
<div class="line"><a id="l00499" name="l00499"></a><span class="lineno">  499</span><span class="comment">   * `output_whether_should_log(..., C)` for which `(X = C.payload_type()) == T`, the following also holds:</span></div>
<div class="line"><a id="l00500" name="l00500"></a><span class="lineno">  500</span><span class="comment">   * `&amp;X == &amp;T`.  In particular, if you can guarantee that all relevant log call sites occur *not* from across</span></div>
<div class="line"><a id="l00501" name="l00501"></a><span class="lineno">  501</span><span class="comment">   * a shared-object boundary from the present call, then it is safe to set `F == true`.  As a corollary, if all</span></div>
<div class="line"><a id="l00502" name="l00502"></a><span class="lineno">  502</span><span class="comment">   * relevant code is statically linked, then `F == true` is also OK.</span></div>
<div class="line"><a id="l00503" name="l00503"></a><span class="lineno">  503</span><span class="comment">   *</span></div>
<div class="line"><a id="l00504" name="l00504"></a><span class="lineno">  504</span><span class="comment">   * Informally: the more of your init_component_to_union_idx_mapping() calls -- ideally all of them -- set</span></div>
<div class="line"><a id="l00505" name="l00505"></a><span class="lineno">  505</span><span class="comment">   * `component_payload_type_info_ptr_is_uniq == true`, the better the performance of output_whether_should_log()</span></div>
<div class="line"><a id="l00506" name="l00506"></a><span class="lineno">  506</span><span class="comment">   * (and therefore relevant Logger::should_log() and therefore relevant `FLOW_LOG_...()` calls of most kinds</span></div>
<div class="line"><a id="l00507" name="l00507"></a><span class="lineno">  507</span><span class="comment">   * -- very much including those that will *not* pass the should-log filter and hence will not log).  This can have</span></div>
<div class="line"><a id="l00508" name="l00508"></a><span class="lineno">  508</span><span class="comment">   * a *significant* impact on your overall performance.</span></div>
<div class="line"><a id="l00509" name="l00509"></a><span class="lineno">  509</span><span class="comment">   *</span></div>
<div class="line"><a id="l00510" name="l00510"></a><span class="lineno">  510</span><span class="comment">   * @see log::Config doc header Performance section for overall recipe w/r/t perf.</span></div>
<div class="line"><a id="l00511" name="l00511"></a><span class="lineno">  511</span><span class="comment">   *</span></div>
<div class="line"><a id="l00512" name="l00512"></a><span class="lineno">  512</span><span class="comment">   * @internal</span></div>
<div class="line"><a id="l00513" name="l00513"></a><span class="lineno">  513</span><span class="comment">   * ### Rationale for `enum_sparse_length` ###</span></div>
<div class="line"><a id="l00514" name="l00514"></a><span class="lineno">  514</span><span class="comment">   * A design is possible (and indeed was used for a very brief period of time) that avoids the need for this arg.</span></div>
<div class="line"><a id="l00515" name="l00515"></a><span class="lineno">  515</span><span class="comment">   * Internally #m_verbosities_by_component can be a nice, elegant `unordered_map&lt;component_union_idx_t, Sev&gt;`, in which</span></div>
<div class="line"><a id="l00516" name="l00516"></a><span class="lineno">  516</span><span class="comment">   * case we need not know anything about how many `enum` values there can be, and as long as the various `enum`s&#39;</span></div>
<div class="line"><a id="l00517" name="l00517"></a><span class="lineno">  517</span><span class="comment">   * numeric values don&#39;t clash -- which must and should easily be avoided by the user calling us here -- everything</span></div>
<div class="line"><a id="l00518" name="l00518"></a><span class="lineno">  518</span><span class="comment">   * works fine with this non-sparse data structure.  However, to make #m_verbosities_by_component a sparse `vector&lt;&gt;`</span></div>
<div class="line"><a id="l00519" name="l00519"></a><span class="lineno">  519</span><span class="comment">   * (that uses `component_union_idx_t` as the key) -- yet never need to `resize()` it when</span></div>
<div class="line"><a id="l00520" name="l00520"></a><span class="lineno">  520</span><span class="comment">   * configure_component_verbosity() is called -- one must know `enum_sparse_length` ahead of time to ensure there</span></div>
<div class="line"><a id="l00521" name="l00521"></a><span class="lineno">  521</span><span class="comment">   * is enough space in the `vector` ahead of time.  Why would one use such an ugly (and somewhat space-wasting)</span></div>
<div class="line"><a id="l00522" name="l00522"></a><span class="lineno">  522</span><span class="comment">   * structure instead, you ask?  Answer: Short version: for efficient thread safety of configure_component_verbosity()</span></div>
<div class="line"><a id="l00523" name="l00523"></a><span class="lineno">  523</span><span class="comment">   * and output_whether_should_log().  Long version: See #m_verbosities_by_component doc header.</span></div>
<div class="line"><a id="l00524" name="l00524"></a><span class="lineno">  524</span><span class="comment">   * @endinternal</span></div>
<div class="line"><a id="l00525" name="l00525"></a><span class="lineno">  525</span><span class="comment">   *</span></div>
<div class="line"><a id="l00526" name="l00526"></a><span class="lineno">  526</span><span class="comment">   * @see Component::payload_type() doc header.</span></div>
<div class="line"><a id="l00527" name="l00527"></a><span class="lineno">  527</span><span class="comment">   *</span></div>
<div class="line"><a id="l00528" name="l00528"></a><span class="lineno">  528</span><span class="comment">   * @tparam Component_payload</span></div>
<div class="line"><a id="l00529" name="l00529"></a><span class="lineno">  529</span><span class="comment">   *         See the doc header for the template param `Payload` on Component::payload().</span></div>
<div class="line"><a id="l00530" name="l00530"></a><span class="lineno">  530</span><span class="comment">   *         In addition, in our context, it must be convertible to `component_union_idx_t` (an unsigned integer).</span></div>
<div class="line"><a id="l00531" name="l00531"></a><span class="lineno">  531</span><span class="comment">   *         Informally, `Component_payload` must be a sane unsigned `enum` with end sentinel `S_END_SENTINEL`.</span></div>
<div class="line"><a id="l00532" name="l00532"></a><span class="lineno">  532</span><span class="comment">   *         The various input Component_payload types are distinguished via `typeid(Component_payload)`</span></div>
<div class="line"><a id="l00533" name="l00533"></a><span class="lineno">  533</span><span class="comment">   *         and further possibly `type_index(typeid(Component_payload))`.  I provide this implementation detail purely</span></div>
<div class="line"><a id="l00534" name="l00534"></a><span class="lineno">  534</span><span class="comment">   *         for general context; it should not be seen as relevant to how one uses the API.</span></div>
<div class="line"><a id="l00535" name="l00535"></a><span class="lineno">  535</span><span class="comment">   * @param enum_to_num_offset</span></div>
<div class="line"><a id="l00536" name="l00536"></a><span class="lineno">  536</span><span class="comment">   *        For each further-referenced `Component_payload` value C, its flat union index shall be</span></div>
<div class="line"><a id="l00537" name="l00537"></a><span class="lineno">  537</span><span class="comment">   *        `component_union_idx_t(C) + enum_to_num_offset`.</span></div>
<div class="line"><a id="l00538" name="l00538"></a><span class="lineno">  538</span><span class="comment">   *        So this is the &quot;base&quot; index for the `enum` you are registering, in the final flat table of components.</span></div>
<div class="line"><a id="l00539" name="l00539"></a><span class="lineno">  539</span><span class="comment">   * @param enum_sparse_length</span></div>
<div class="line"><a id="l00540" name="l00540"></a><span class="lineno">  540</span><span class="comment">   *        Formally, one plus the highest numeric value of a `Component_payload` value that will ever be passed to</span></div>
<div class="line"><a id="l00541" name="l00541"></a><span class="lineno">  541</span><span class="comment">   *        configure_component_verbosity() (directly; or indirectly if using configure_component_verbosity_by_name()).</span></div>
<div class="line"><a id="l00542" name="l00542"></a><span class="lineno">  542</span><span class="comment">   *        Informally, we recommend that you (a) use the config_enum_start_hdr.macros.hpp mechanism to create</span></div>
<div class="line"><a id="l00543" name="l00543"></a><span class="lineno">  543</span><span class="comment">   *        `Component_payload` type in the first place; and (b) therefore use</span></div>
<div class="line"><a id="l00544" name="l00544"></a><span class="lineno">  544</span><span class="comment">   *        `standard_component_payload_enum_sparse_length&lt;Component_payload&gt;()` for the present arg&#39;s value.</span></div>
<div class="line"><a id="l00545" name="l00545"></a><span class="lineno">  545</span><span class="comment">   * @param component_payload_type_info_ptr_is_uniq</span></div>
<div class="line"><a id="l00546" name="l00546"></a><span class="lineno">  546</span><span class="comment">   *        Potentially important for perf!  See above.</span></div>
<div class="line"><a id="l00547" name="l00547"></a><span class="lineno">  547</span><span class="comment">   */</span></div>
<div class="line"><a id="l00548" name="l00548"></a><span class="lineno">  548</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l00549" name="l00549"></a><span class="lineno">  549</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a9b7ba819538d221f190e044cfa6220db">init_component_to_union_idx_mapping</a>(<a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a> enum_to_num_offset,</div>
<div class="line"><a id="l00550" name="l00550"></a><span class="lineno">  550</span>                                           <span class="keywordtype">size_t</span> enum_sparse_length,</div>
<div class="line"><a id="l00551" name="l00551"></a><span class="lineno">  551</span>                                           <span class="keywordtype">bool</span> component_payload_type_info_ptr_is_uniq = <span class="keyword">false</span>);</div>
<div class="line"><a id="l00552" name="l00552"></a><span class="lineno">  552</span><span class="comment"></span> </div>
<div class="line"><a id="l00553" name="l00553"></a><span class="lineno">  553</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00554" name="l00554"></a><span class="lineno">  554</span><span class="comment">   * Registers the string names of each member of the `enum class Component_payload` earlier registered via</span></div>
<div class="line"><a id="l00555" name="l00555"></a><span class="lineno">  555</span><span class="comment">   * `init_component_to_union_idx_mapping&lt;Component_payload&gt;()`.  These are used subsequently (as of this writing)</span></div>
<div class="line"><a id="l00556" name="l00556"></a><span class="lineno">  556</span><span class="comment">   * to (1) map name to index in one of the `configure_component_verbosity*()` methods; and</span></div>
<div class="line"><a id="l00557" name="l00557"></a><span class="lineno">  557</span><span class="comment">   * (2) to map index to name in output_component_to_ostream().</span></div>
<div class="line"><a id="l00558" name="l00558"></a><span class="lineno">  558</span><span class="comment">   *</span></div>
<div class="line"><a id="l00559" name="l00559"></a><span class="lineno">  559</span><span class="comment">   * Behavior undefined if `init_component_to_union_idx_mapping&lt;Component_payload&gt;()` hasn&#39;t yet been called.</span></div>
<div class="line"><a id="l00560" name="l00560"></a><span class="lineno">  560</span><span class="comment">   * Behavior undefined if `init_component_names&lt;Component_payload&gt;()` has already been called.  (Informally, something</span></div>
<div class="line"><a id="l00561" name="l00561"></a><span class="lineno">  561</span><span class="comment">   * safe might happen, depending, but in general it&#39;s a weird/bad idea, so don&#39;t.)  Behavior undefined if</span></div>
<div class="line"><a id="l00562" name="l00562"></a><span class="lineno">  562</span><span class="comment">   * any value in `component_names` is empty.</span></div>
<div class="line"><a id="l00563" name="l00563"></a><span class="lineno">  563</span><span class="comment">   *</span></div>
<div class="line"><a id="l00564" name="l00564"></a><span class="lineno">  564</span><span class="comment">   * The recommended (but not mandatory) way to auto-generate a `component_names` map (as normally doing so by hand is</span></div>
<div class="line"><a id="l00565" name="l00565"></a><span class="lineno">  565</span><span class="comment">   * tedious) is to use `config_enum_{start|end}_macros.[hc]pp`.  As an example, Flow itself does it in</span></div>
<div class="line"><a id="l00566" name="l00566"></a><span class="lineno">  566</span><span class="comment">   * common.hpp and common.cpp, defining both flow::Flow_log_component (the `enum`) and</span></div>
<div class="line"><a id="l00567" name="l00567"></a><span class="lineno">  567</span><span class="comment">   * flow::S_FLOW_LOG_COMPONENT_NAME_MAP (the `component_names` map).  Basically, via macro magic it names each</span></div>
<div class="line"><a id="l00568" name="l00568"></a><span class="lineno">  568</span><span class="comment">   * component according to the `enum` member identifier&#39;s own name.</span></div>
<div class="line"><a id="l00569" name="l00569"></a><span class="lineno">  569</span><span class="comment">   *</span></div>
<div class="line"><a id="l00570" name="l00570"></a><span class="lineno">  570</span><span class="comment">   * ### `component_names` meaning ###</span></div>
<div class="line"><a id="l00571" name="l00571"></a><span class="lineno">  571</span><span class="comment">   * Some subtleties exist in interpreting `component_names`.</span></div>
<div class="line"><a id="l00572" name="l00572"></a><span class="lineno">  572</span><span class="comment">   *</span></div>
<div class="line"><a id="l00573" name="l00573"></a><span class="lineno">  573</span><span class="comment">   * Firstly, each value (string name) in `component_names` -- as well as `payload_type_prefix_or_empty` -- is</span></div>
<div class="line"><a id="l00574" name="l00574"></a><span class="lineno">  574</span><span class="comment">   * internally pre-normalized before any other work.  Name normalization consists of conversion to upper case according</span></div>
<div class="line"><a id="l00575" name="l00575"></a><span class="lineno">  575</span><span class="comment">   * to the classic (&quot;C&quot;) locale.  output_component_to_ostream() will print in normalized form (if applicable);</span></div>
<div class="line"><a id="l00576" name="l00576"></a><span class="lineno">  576</span><span class="comment">   * and configure_component_verbosity_by_name() will normalize the input arg string before lookup.</span></div>
<div class="line"><a id="l00577" name="l00577"></a><span class="lineno">  577</span><span class="comment">   *</span></div>
<div class="line"><a id="l00578" name="l00578"></a><span class="lineno">  578</span><span class="comment">   * If empty, `payload_type_prefix_or_empty` has no effect.  Otherwise, its effect is as if it *were* empty, but</span></div>
<div class="line"><a id="l00579" name="l00579"></a><span class="lineno">  579</span><span class="comment">   * as if `component_names[X]` had `payload_type_prefix_or_empty` prepended to its actual value at all times.</span></div>
<div class="line"><a id="l00580" name="l00580"></a><span class="lineno">  580</span><span class="comment">   * Less formally, it&#39;s a constant to prefix every name; then if the program (perhaps around `main()`) simply manually</span></div>
<div class="line"><a id="l00581" name="l00581"></a><span class="lineno">  581</span><span class="comment">   * provides a distinct, cosmetically useful &quot;namespace-like&quot; prefix in each init_component_names() call, then</span></div>
<div class="line"><a id="l00582" name="l00582"></a><span class="lineno">  582</span><span class="comment">   * it can 100% guarantee no name clashes, even if accidentally one of module X&#39;s component names A happened to</span></div>
<div class="line"><a id="l00583" name="l00583"></a><span class="lineno">  583</span><span class="comment">   * equal an unrelated module Y&#39;s component name B.  For example, A = B = &quot;UTIL&quot; is fairly likely to collide otherwise.</span></div>
<div class="line"><a id="l00584" name="l00584"></a><span class="lineno">  584</span><span class="comment">   * It won&#39;t be an issue, if they end up being called &quot;X_UTIL&quot; and &quot;Y_UTIL&quot; ultimately, by supplying</span></div>
<div class="line"><a id="l00585" name="l00585"></a><span class="lineno">  585</span><span class="comment">   * prefixes &quot;X_&quot; and &quot;Y_&quot; X and Y&#39;s init_component_names() calls.</span></div>
<div class="line"><a id="l00586" name="l00586"></a><span class="lineno">  586</span><span class="comment">   *</span></div>
<div class="line"><a id="l00587" name="l00587"></a><span class="lineno">  587</span><span class="comment">   * Within `component_names` if a value (name) is present 2+ times, behavior is undefined.</span></div>
<div class="line"><a id="l00588" name="l00588"></a><span class="lineno">  588</span><span class="comment">   * Furthermore if `payload_type_prefix_or_empty + X`, where `X` is in `component_names`, is already</span></div>
<div class="line"><a id="l00589" name="l00589"></a><span class="lineno">  589</span><span class="comment">   * stored in `*this`, behavior is undefined.  Either way it&#39;s a name collision which should be entirely avoidable</span></div>
<div class="line"><a id="l00590" name="l00590"></a><span class="lineno">  590</span><span class="comment">   * using `payload_type_prefix_or_empty` as shown above.</span></div>
<div class="line"><a id="l00591" name="l00591"></a><span class="lineno">  591</span><span class="comment">   *</span></div>
<div class="line"><a id="l00592" name="l00592"></a><span class="lineno">  592</span><span class="comment">   * It is a multi-map, and key K is allowed to be present 2+ times mapping to 2+ distinct names.</span></div>
<div class="line"><a id="l00593" name="l00593"></a><span class="lineno">  593</span><span class="comment">   * The reason this is supported is so one can (discouraged though it is -- but for historical reasons tends to</span></div>
<div class="line"><a id="l00594" name="l00594"></a><span class="lineno">  594</span><span class="comment">   * come up at times) declare an `enum` that includes a few mutually &quot;aliased&quot; members:</span></div>
<div class="line"><a id="l00595" name="l00595"></a><span class="lineno">  595</span><span class="comment">   *   - `Sweet_components::S_COOL_ENGINE` &lt;=&gt; &quot;COOL_ENGINE&quot; &lt;=&gt; 5</span></div>
<div class="line"><a id="l00596" name="l00596"></a><span class="lineno">  596</span><span class="comment">   *   - `Sweet_components::S_ENGINE_ALIAS1` &lt;=&gt; &quot;ENGINE_ALIAS1&quot; &lt;=&gt; 5</span></div>
<div class="line"><a id="l00597" name="l00597"></a><span class="lineno">  597</span><span class="comment">   *   - `Sweet_components::S_ENGINE_ALIAS2` &lt;=&gt; &quot;ENGINE_ALIAS2&quot; &lt;=&gt; 5</span></div>
<div class="line"><a id="l00598" name="l00598"></a><span class="lineno">  598</span><span class="comment">   * In that example, any of `S_{COOL_ENGINE|ENGINE_ALIAS{1|2}}` maps to the rather long name</span></div>
<div class="line"><a id="l00599" name="l00599"></a><span class="lineno">  599</span><span class="comment">   * &quot;COOL_ENGINE,ENGINE_ALIAS1,ENGINE_ALIAS2&quot;; and *each* of &quot;COOL_ENGINE&quot;, &quot;ENGINE_ALIAS1&quot;,</span></div>
<div class="line"><a id="l00600" name="l00600"></a><span class="lineno">  600</span><span class="comment">   * &quot;ENGINE_ALIAS2&quot; maps backwards to a single entry in the component-to-verbosity table.  Hence if I configure</span></div>
<div class="line"><a id="l00601" name="l00601"></a><span class="lineno">  601</span><span class="comment">   * verbosity X (using `configure_component_verbosity*()`) for COOL_ENGINE_ALIAS1, then verbosity X config will equally</span></div>
<div class="line"><a id="l00602" name="l00602"></a><span class="lineno">  602</span><span class="comment">   * affect subsequent messages with specified component COOL_ENGINE and ENGINE_ALIAS2 as well.</span></div>
<div class="line"><a id="l00603" name="l00603"></a><span class="lineno">  603</span><span class="comment">   *</span></div>
<div class="line"><a id="l00604" name="l00604"></a><span class="lineno">  604</span><span class="comment">   * Detail: When concatenating component output names as just described, the prefix `payload_type_prefix_or_empty`</span></div>
<div class="line"><a id="l00605" name="l00605"></a><span class="lineno">  605</span><span class="comment">   * is prepended only once.  So, if the prefix is &quot;SWEET-&quot;, then any one of the above 3 `enum` example members</span></div>
<div class="line"><a id="l00606" name="l00606"></a><span class="lineno">  606</span><span class="comment">   * maps to the name &quot;SWEET-COOL_ENGINE,ENGINE_ALIAS1,ENGINE_ALIAS2&quot;.</span></div>
<div class="line"><a id="l00607" name="l00607"></a><span class="lineno">  607</span><span class="comment">   *</span></div>
<div class="line"><a id="l00608" name="l00608"></a><span class="lineno">  608</span><span class="comment">   * `output_components_numerically`, if and only if set to `true`, suppresses the default behavior which is to</span></div>
<div class="line"><a id="l00609" name="l00609"></a><span class="lineno">  609</span><span class="comment">   * memorize the string to output (in output_component_to_ostream()) for a given `enum` value;</span></div>
<div class="line"><a id="l00610" name="l00610"></a><span class="lineno">  610</span><span class="comment">   * instead it doesn&#39;t memorize this forward mapping.  As a result, output_component_to_ostream() will simply output</span></div>
<div class="line"><a id="l00611" name="l00611"></a><span class="lineno">  611</span><span class="comment">   * the *numerical* value of the `enum` member from the flat union component table.  This is a cosmetic output choice</span></div>
<div class="line"><a id="l00612" name="l00612"></a><span class="lineno">  612</span><span class="comment">   * some prefer to the long-looking component names.</span></div>
<div class="line"><a id="l00613" name="l00613"></a><span class="lineno">  613</span><span class="comment">   *</span></div>
<div class="line"><a id="l00614" name="l00614"></a><span class="lineno">  614</span><span class="comment">   * In addition, even if `!output_components_numerically`, but a subsequent output_component_to_ostream() call</span></div>
<div class="line"><a id="l00615" name="l00615"></a><span class="lineno">  615</span><span class="comment">   * encounters an `enum` value that you neglected to register via init_component_names() (omitting it in</span></div>
<div class="line"><a id="l00616" name="l00616"></a><span class="lineno">  616</span><span class="comment">   * `component_names` in particular), then it will also be printed numerically as if `output_components_numerically`.</span></div>
<div class="line"><a id="l00617" name="l00617"></a><span class="lineno">  617</span><span class="comment">   *</span></div>
<div class="line"><a id="l00618" name="l00618"></a><span class="lineno">  618</span><span class="comment">   * Finally, even if `output_components_numerically == true`, the backwards mapping (from string name to component)</span></div>
<div class="line"><a id="l00619" name="l00619"></a><span class="lineno">  619</span><span class="comment">   * is still memorized.  Therefore one can still set configure_component_verbosity_by_name() by string name.</span></div>
<div class="line"><a id="l00620" name="l00620"></a><span class="lineno">  620</span><span class="comment">   * Again, in practice, I have seen this: Config files will refer to component verbosities by component name, not</span></div>
<div class="line"><a id="l00621" name="l00621"></a><span class="lineno">  621</span><span class="comment">   * unhelpful-looking number; but output log files still print them as numbers for brevity.</span></div>
<div class="line"><a id="l00622" name="l00622"></a><span class="lineno">  622</span><span class="comment">   *</span></div>
<div class="line"><a id="l00623" name="l00623"></a><span class="lineno">  623</span><span class="comment">   * @param component_names</span></div>
<div class="line"><a id="l00624" name="l00624"></a><span class="lineno">  624</span><span class="comment">   *        Mapping of each possible Component_payload value to its string representation, for both output and</span></div>
<div class="line"><a id="l00625" name="l00625"></a><span class="lineno">  625</span><span class="comment">   *        per-component config (namely verbosity config) subsequently.  Details above.</span></div>
<div class="line"><a id="l00626" name="l00626"></a><span class="lineno">  626</span><span class="comment">   *        Empty names lead to undefined behavior.</span></div>
<div class="line"><a id="l00627" name="l00627"></a><span class="lineno">  627</span><span class="comment">   * @param output_components_numerically</span></div>
<div class="line"><a id="l00628" name="l00628"></a><span class="lineno">  628</span><span class="comment">   *        If and only if `true`, output_component_to_ostream() will output the flat numeric index for all</span></div>
<div class="line"><a id="l00629" name="l00629"></a><span class="lineno">  629</span><span class="comment">   *        `Component_payload`-passing log call sites; else it will print the string name from the map</span></div>
<div class="line"><a id="l00630" name="l00630"></a><span class="lineno">  630</span><span class="comment">   *        (but if not *in* the map, then it&#39;ll fall back to the flat index again).</span></div>
<div class="line"><a id="l00631" name="l00631"></a><span class="lineno">  631</span><span class="comment">   * @param payload_type_prefix_or_empty</span></div>
<div class="line"><a id="l00632" name="l00632"></a><span class="lineno">  632</span><span class="comment">   *        Optional prefix helpful as a disambiguating &quot;namespace&quot; to preprend to values in `component_names`.</span></div>
<div class="line"><a id="l00633" name="l00633"></a><span class="lineno">  633</span><span class="comment">   *        Details above.</span></div>
<div class="line"><a id="l00634" name="l00634"></a><span class="lineno">  634</span><span class="comment">   * */</span></div>
<div class="line"><a id="l00635" name="l00635"></a><span class="lineno">  635</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l00636" name="l00636"></a><span class="lineno">  636</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a146a60d96256dbaed4f5f0e7dcd8f529">init_component_names</a>(<span class="keyword">const</span> boost::unordered_multimap&lt;Component_payload, std::string&gt;&amp; component_names,</div>
<div class="line"><a id="l00637" name="l00637"></a><span class="lineno">  637</span>                            <span class="keywordtype">bool</span> output_components_numerically = <span class="keyword">false</span>,</div>
<div class="line"><a id="l00638" name="l00638"></a><span class="lineno">  638</span>                            <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> payload_type_prefix_or_empty = <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a>());</div>
<div class="line"><a id="l00639" name="l00639"></a><span class="lineno">  639</span><span class="comment"></span> </div>
<div class="line"><a id="l00640" name="l00640"></a><span class="lineno">  640</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00641" name="l00641"></a><span class="lineno">  641</span><span class="comment">   * Sets the default verbosity to the given value, to be used by subsequent output_whether_should_log() calls whenever</span></div>
<div class="line"><a id="l00642" name="l00642"></a><span class="lineno">  642</span><span class="comment">   * one supplies it a component for which no per-component verbosity is configured at that time; optionally wipes out</span></div>
<div class="line"><a id="l00643" name="l00643"></a><span class="lineno">  643</span><span class="comment">   * all existing per-component verbosities for a constructor-like reset.</span></div>
<div class="line"><a id="l00644" name="l00644"></a><span class="lineno">  644</span><span class="comment">   *</span></div>
<div class="line"><a id="l00645" name="l00645"></a><span class="lineno">  645</span><span class="comment">   * This is fairly intuitive; the only aspect one might find non-obvious is `reset == true` mode.</span></div>
<div class="line"><a id="l00646" name="l00646"></a><span class="lineno">  646</span><span class="comment">   * In that mode all per-component verbosities are forgotten, as after construction.  An intended use scenario is</span></div>
<div class="line"><a id="l00647" name="l00647"></a><span class="lineno">  647</span><span class="comment">   * when reading a hypothetical config file describing new, dynamic *overall* verbosity settings to replace any</span></div>
<div class="line"><a id="l00648" name="l00648"></a><span class="lineno">  648</span><span class="comment">   * existing ones.  Such a config file would probably specify the catch-all (default) verbosity; then 0 or more</span></div>
<div class="line"><a id="l00649" name="l00649"></a><span class="lineno">  649</span><span class="comment">   * per-component &quot;exception&quot; verbosities.  Hence once would call this method with `reset == true` accordingly to</span></div>
<div class="line"><a id="l00650" name="l00650"></a><span class="lineno">  650</span><span class="comment">   * reset everything and set the default; then one would call `configure_component_verbosity*()` for each &quot;exception.&quot;</span></div>
<div class="line"><a id="l00651" name="l00651"></a><span class="lineno">  651</span><span class="comment">   *</span></div>
<div class="line"><a id="l00652" name="l00652"></a><span class="lineno">  652</span><span class="comment">   * `reset == true` is technically slower than otherwise, though it is doubtful one would call us frequently enough</span></div>
<div class="line"><a id="l00653" name="l00653"></a><span class="lineno">  653</span><span class="comment">   * for it to matter.  The perf cost of `!reset` is constant time and basically that of a scalar assignment.</span></div>
<div class="line"><a id="l00654" name="l00654"></a><span class="lineno">  654</span><span class="comment">   * The perf cost of `reset == true` is that plus the cost of about N configure_component_verbosity() calls, where</span></div>
<div class="line"><a id="l00655" name="l00655"></a><span class="lineno">  655</span><span class="comment">   * N is the highest flat-union-component-table implied by the `enum_sparse_length` arg</span></div>
<div class="line"><a id="l00656" name="l00656"></a><span class="lineno">  656</span><span class="comment">   * to init_component_to_union_idx_mapping() calls to date.  In practice doing this when</span></div>
<div class="line"><a id="l00657" name="l00657"></a><span class="lineno">  657</span><span class="comment">   * outside config changes is unlikely to be a perf issue.</span></div>
<div class="line"><a id="l00658" name="l00658"></a><span class="lineno">  658</span><span class="comment">   *</span></div>
<div class="line"><a id="l00659" name="l00659"></a><span class="lineno">  659</span><span class="comment">   * ### Thread safety on `*this` ###</span></div>
<div class="line"><a id="l00660" name="l00660"></a><span class="lineno">  660</span><span class="comment">   * If called, it must be called after all init_component_to_union_idx_mapping() calls have completed.</span></div>
<div class="line"><a id="l00661" name="l00661"></a><span class="lineno">  661</span><span class="comment">   * It is safe to call concurrently with output_whether_should_log(), meaning dynamic config of verbosities is</span></div>
<div class="line"><a id="l00662" name="l00662"></a><span class="lineno">  662</span><span class="comment">   * allowed.  See formal details in thread safety notes in class Config doc header.</span></div>
<div class="line"><a id="l00663" name="l00663"></a><span class="lineno">  663</span><span class="comment">   *</span></div>
<div class="line"><a id="l00664" name="l00664"></a><span class="lineno">  664</span><span class="comment">   * @param most_verbose_sev_default</span></div>
<div class="line"><a id="l00665" name="l00665"></a><span class="lineno">  665</span><span class="comment">   *        The most-verbose (numerically highest) `Sev sev` value such that output_whether_should_log() will return</span></div>
<div class="line"><a id="l00666" name="l00666"></a><span class="lineno">  666</span><span class="comment">   *        `true`, when `Component component` is either null or has no per-component verbosity configured at that time.</span></div>
<div class="line"><a id="l00667" name="l00667"></a><span class="lineno">  667</span><span class="comment">   * @param reset</span></div>
<div class="line"><a id="l00668" name="l00668"></a><span class="lineno">  668</span><span class="comment">   *        If `false` then per-component verbosities are left unchanged; else they are wiped out, meaning only the</span></div>
<div class="line"><a id="l00669" name="l00669"></a><span class="lineno">  669</span><span class="comment">   *        catch-all setting has subsequent effect in output_whether_should_log().</span></div>
<div class="line"><a id="l00670" name="l00670"></a><span class="lineno">  670</span><span class="comment">   */</span></div>
<div class="line"><a id="l00671" name="l00671"></a><span class="lineno">  671</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#ac562cc0132f6cfa81b42c332400033ae">configure_default_verbosity</a>(<a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> most_verbose_sev_default, <span class="keywordtype">bool</span> reset);</div>
<div class="line"><a id="l00672" name="l00672"></a><span class="lineno">  672</span><span class="comment"></span> </div>
<div class="line"><a id="l00673" name="l00673"></a><span class="lineno">  673</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00674" name="l00674"></a><span class="lineno">  674</span><span class="comment">   * Sets the per-component verbosity for the given component to the given value, to be used by subsequent</span></div>
<div class="line"><a id="l00675" name="l00675"></a><span class="lineno">  675</span><span class="comment">   * output_whether_should_log() calls whenever one supplies it the same component value.  See also</span></div>
<div class="line"><a id="l00676" name="l00676"></a><span class="lineno">  676</span><span class="comment">   * configure_default_verbosity().</span></div>
<div class="line"><a id="l00677" name="l00677"></a><span class="lineno">  677</span><span class="comment">   *</span></div>
<div class="line"><a id="l00678" name="l00678"></a><span class="lineno">  678</span><span class="comment">   * This only works (and will return `true`) if `init_component_to_union_idx_mapping&lt;Component_payload&gt;()` has been</span></div>
<div class="line"><a id="l00679" name="l00679"></a><span class="lineno">  679</span><span class="comment">   * called.  Otherwise it returns `false` (caller may `assert()` against this result if it is felt justified).</span></div>
<div class="line"><a id="l00680" name="l00680"></a><span class="lineno">  680</span><span class="comment">   *</span></div>
<div class="line"><a id="l00681" name="l00681"></a><span class="lineno">  681</span><span class="comment">   * See class doc header section &quot;What Config controls and how&quot; for more discussion.</span></div>
<div class="line"><a id="l00682" name="l00682"></a><span class="lineno">  682</span><span class="comment">   *</span></div>
<div class="line"><a id="l00683" name="l00683"></a><span class="lineno">  683</span><span class="comment">   * @param most_verbose_sev</span></div>
<div class="line"><a id="l00684" name="l00684"></a><span class="lineno">  684</span><span class="comment">   *        The most-verbose (numerically highest) `Sev sev` value such that output_whether_should_log() will return</span></div>
<div class="line"><a id="l00685" name="l00685"></a><span class="lineno">  685</span><span class="comment">   *        `true`, when `Component component` is not null and has `Component::payload&lt;Component_payload&gt;()`</span></div>
<div class="line"><a id="l00686" name="l00686"></a><span class="lineno">  686</span><span class="comment">   *        return a value equal to `component_payload`.</span></div>
<div class="line"><a id="l00687" name="l00687"></a><span class="lineno">  687</span><span class="comment">   * @param component_payload</span></div>
<div class="line"><a id="l00688" name="l00688"></a><span class="lineno">  688</span><span class="comment">   *        The component for which verbosity is being set.</span></div>
<div class="line"><a id="l00689" name="l00689"></a><span class="lineno">  689</span><span class="comment">   * @return `true` on success; `false` otherwise.  See above for more.</span></div>
<div class="line"><a id="l00690" name="l00690"></a><span class="lineno">  690</span><span class="comment">   */</span></div>
<div class="line"><a id="l00691" name="l00691"></a><span class="lineno">  691</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l00692" name="l00692"></a><span class="lineno">  692</span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#adfde40890c0dc1fa8956451f44251dc8">configure_component_verbosity</a>(<a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> most_verbose_sev, Component_payload component_payload);</div>
<div class="line"><a id="l00693" name="l00693"></a><span class="lineno">  693</span><span class="comment"></span> </div>
<div class="line"><a id="l00694" name="l00694"></a><span class="lineno">  694</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00695" name="l00695"></a><span class="lineno">  695</span><span class="comment">   * Like configure_component_verbosity(), but the component is to be specified by its registered string</span></div>
<div class="line"><a id="l00696" name="l00696"></a><span class="lineno">  696</span><span class="comment">   * name, well suited to interpreting text config files.  The meaning of verbosity is the same as in the other</span></div>
<div class="line"><a id="l00697" name="l00697"></a><span class="lineno">  697</span><span class="comment">   * overload.</span></div>
<div class="line"><a id="l00698" name="l00698"></a><span class="lineno">  698</span><span class="comment">   *</span></div>
<div class="line"><a id="l00699" name="l00699"></a><span class="lineno">  699</span><span class="comment">   * This only works (and will return `true`) if init_component_names() has been called in such a way as to</span></div>
<div class="line"><a id="l00700" name="l00700"></a><span class="lineno">  700</span><span class="comment">   * successfully associate a component in the flat union table with the name equal (after normalization of both sides)</span></div>
<div class="line"><a id="l00701" name="l00701"></a><span class="lineno">  701</span><span class="comment">   * to `component_name`.  If the name is unknown, it returns `false`.</span></div>
<div class="line"><a id="l00702" name="l00702"></a><span class="lineno">  702</span><span class="comment">   *</span></div>
<div class="line"><a id="l00703" name="l00703"></a><span class="lineno">  703</span><span class="comment">   * Name normalization consists of conversion to upper case according to the classic (&quot;C&quot;) locale.</span></div>
<div class="line"><a id="l00704" name="l00704"></a><span class="lineno">  704</span><span class="comment">   *</span></div>
<div class="line"><a id="l00705" name="l00705"></a><span class="lineno">  705</span><span class="comment">   * See class doc header section &quot;What Config controls and how&quot; for more discussion.</span></div>
<div class="line"><a id="l00706" name="l00706"></a><span class="lineno">  706</span><span class="comment">   *</span></div>
<div class="line"><a id="l00707" name="l00707"></a><span class="lineno">  707</span><span class="comment">   * @param most_verbose_sev</span></div>
<div class="line"><a id="l00708" name="l00708"></a><span class="lineno">  708</span><span class="comment">   *        The most-verbose (numerically highest) `Sev sev` value such that output_whether_should_log() will return</span></div>
<div class="line"><a id="l00709" name="l00709"></a><span class="lineno">  709</span><span class="comment">   *        `true`, when `Component component` is not null and has an associated string name equal to `component_name`</span></div>
<div class="line"><a id="l00710" name="l00710"></a><span class="lineno">  710</span><span class="comment">   *        (post-normalization of both sides of comparison).</span></div>
<div class="line"><a id="l00711" name="l00711"></a><span class="lineno">  711</span><span class="comment">   * @param component_name</span></div>
<div class="line"><a id="l00712" name="l00712"></a><span class="lineno">  712</span><span class="comment">   *        The component for which verbosity is being set.</span></div>
<div class="line"><a id="l00713" name="l00713"></a><span class="lineno">  713</span><span class="comment">   * @return `true` on success; `false` otherwise.  See above for more.</span></div>
<div class="line"><a id="l00714" name="l00714"></a><span class="lineno">  714</span><span class="comment">   */</span></div>
<div class="line"><a id="l00715" name="l00715"></a><span class="lineno">  715</span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a2f266ee7e22d1090ab4de76e532cab89">configure_component_verbosity_by_name</a>(<a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> most_verbose_sev,</div>
<div class="line"><a id="l00716" name="l00716"></a><span class="lineno">  716</span>                                             <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> component_name);</div>
<div class="line"><a id="l00717" name="l00717"></a><span class="lineno">  717</span><span class="comment"></span> </div>
<div class="line"><a id="l00718" name="l00718"></a><span class="lineno">  718</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00719" name="l00719"></a><span class="lineno">  719</span><span class="comment">   * Returns highest numeric value in the given component-payload `enum`, plus 1, assuming that</span></div>
<div class="line"><a id="l00720" name="l00720"></a><span class="lineno">  720</span><span class="comment">   * `enum` was created using the config_enum_start_hdr.macros.hpp mechanism with all requirements followed by</span></div>
<div class="line"><a id="l00721" name="l00721"></a><span class="lineno">  721</span><span class="comment">   * user.  This is useful for most invocations of init_component_to_union_idx_mapping() for its</span></div>
<div class="line"><a id="l00722" name="l00722"></a><span class="lineno">  722</span><span class="comment">   * `enum_sparse_length` argument.</span></div>
<div class="line"><a id="l00723" name="l00723"></a><span class="lineno">  723</span><span class="comment">   *</span></div>
<div class="line"><a id="l00724" name="l00724"></a><span class="lineno">  724</span><span class="comment">   * For example, if one wants to store a `vector` that uses `size_t(X)`, where `X` is a `Component_payload`,</span></div>
<div class="line"><a id="l00725" name="l00725"></a><span class="lineno">  725</span><span class="comment">   * as an associative-key-like index, then the `vector` would have to be sized whatever the present method</span></div>
<div class="line"><a id="l00726" name="l00726"></a><span class="lineno">  726</span><span class="comment">   * returns to guarantee no out-of-bounds error.</span></div>
<div class="line"><a id="l00727" name="l00727"></a><span class="lineno">  727</span><span class="comment">   *</span></div>
<div class="line"><a id="l00728" name="l00728"></a><span class="lineno">  728</span><span class="comment">   * @see init_component_to_union_idx_mapping(), particularly the `enum_sparse_length` argument.</span></div>
<div class="line"><a id="l00729" name="l00729"></a><span class="lineno">  729</span><span class="comment"></span> </div>
<div class="line"><a id="l00730" name="l00730"></a><span class="lineno">  730</span><span class="comment">   * @tparam Component_payload</span></div>
<div class="line"><a id="l00731" name="l00731"></a><span class="lineno">  731</span><span class="comment">   *         An `enum class` type created by the mechanism prescribed in config_enum_start_hdr.macros.hpp, using that</span></div>
<div class="line"><a id="l00732" name="l00732"></a><span class="lineno">  732</span><span class="comment">   *         mechanism and with user following the documented requirements therein.  Alternatively (though it&#39;s</span></div>
<div class="line"><a id="l00733" name="l00733"></a><span class="lineno">  733</span><span class="comment">   *         not recommended) the following is sufficient if one makes the type some other way:</span></div>
<div class="line"><a id="l00734" name="l00734"></a><span class="lineno">  734</span><span class="comment">   *         `Component_payload::S_END_SENTINEL` must have the highest numeric value, without ties;</span></div>
<div class="line"><a id="l00735" name="l00735"></a><span class="lineno">  735</span><span class="comment">   *         and the backing type is unsigned and with a bit width no higher than that of `size_t`</span></div>
<div class="line"><a id="l00736" name="l00736"></a><span class="lineno">  736</span><span class="comment">   *         (Component::enum_raw_t is what the aforementioned standard mechanism uses as of this writing).</span></div>
<div class="line"><a id="l00737" name="l00737"></a><span class="lineno">  737</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00738" name="l00738"></a><span class="lineno">  738</span><span class="comment">   */</span></div>
<div class="line"><a id="l00739" name="l00739"></a><span class="lineno">  739</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l00740" name="l00740"></a><span class="lineno">  740</span>  <span class="keyword">static</span> <span class="keywordtype">size_t</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a12f1147ae51ee6f9645dcd46e67c8410">standard_component_payload_enum_sparse_length</a>();</div>
<div class="line"><a id="l00741" name="l00741"></a><span class="lineno">  741</span><span class="comment"></span> </div>
<div class="line"><a id="l00742" name="l00742"></a><span class="lineno">  742</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00743" name="l00743"></a><span class="lineno">  743</span><span class="comment">   * Returns pointer to this thread&#39;s *mutable* verbosity override, for querying or assignment alike.</span></div>
<div class="line"><a id="l00744" name="l00744"></a><span class="lineno">  744</span><span class="comment">   * The value of this override, at any given time, shall affect output_whether_should_log() return value.</span></div>
<div class="line"><a id="l00745" name="l00745"></a><span class="lineno">  745</span><span class="comment">   * See output_whether_should_log().</span></div>
<div class="line"><a id="l00746" name="l00746"></a><span class="lineno">  746</span><span class="comment">   *</span></div>
<div class="line"><a id="l00747" name="l00747"></a><span class="lineno">  747</span><span class="comment">   * If you would like to query the current setting, use this method.</span></div>
<div class="line"><a id="l00748" name="l00748"></a><span class="lineno">  748</span><span class="comment">   *</span></div>
<div class="line"><a id="l00749" name="l00749"></a><span class="lineno">  749</span><span class="comment">   * If you would like to *modify* the current setting, it is safer and easier to use</span></div>
<div class="line"><a id="l00750" name="l00750"></a><span class="lineno">  750</span><span class="comment">   * this_thread_verbosity_override_auto() which supplies RAII-style auto-restore.</span></div>
<div class="line"><a id="l00751" name="l00751"></a><span class="lineno">  751</span><span class="comment">   *</span></div>
<div class="line"><a id="l00752" name="l00752"></a><span class="lineno">  752</span><span class="comment">   * For each thread:</span></div>
<div class="line"><a id="l00753" name="l00753"></a><span class="lineno">  753</span><span class="comment">   *   - Let `S = *(this_thread_verbosity_override())`.</span></div>
<div class="line"><a id="l00754" name="l00754"></a><span class="lineno">  754</span><span class="comment">   *   - Originally `S == Sev::S_END_SENTINEL`.</span></div>
<div class="line"><a id="l00755" name="l00755"></a><span class="lineno">  755</span><span class="comment">   *     - output_whether_should_log() in this case will therefore disregard `S`, per its doc header.</span></div>
<div class="line"><a id="l00756" name="l00756"></a><span class="lineno">  756</span><span class="comment">   *   - You may set `S` to any valid log::Sev value via direct assignment.</span></div>
<div class="line"><a id="l00757" name="l00757"></a><span class="lineno">  757</span><span class="comment">   *     - output_whether_should_log() in this case will follow `S` and only `S`, per its doc header.</span></div>
<div class="line"><a id="l00758" name="l00758"></a><span class="lineno">  758</span><span class="comment">   *     - this_thread_verbosity_override_auto() is a convenient way of doing this, as it&#39;ll take care of the next</span></div>
<div class="line"><a id="l00759" name="l00759"></a><span class="lineno">  759</span><span class="comment">   *       step with minimal effort:</span></div>
<div class="line"><a id="l00760" name="l00760"></a><span class="lineno">  760</span><span class="comment">   *   - You may set `S` back to Sev::S_END_SENTINEL.</span></div>
<div class="line"><a id="l00761" name="l00761"></a><span class="lineno">  761</span><span class="comment">   *     - output_whether_should_log() will begin disregarding `S` again.</span></div>
<div class="line"><a id="l00762" name="l00762"></a><span class="lineno">  762</span><span class="comment">   *</span></div>
<div class="line"><a id="l00763" name="l00763"></a><span class="lineno">  763</span><span class="comment">   * @return See above.  Note that, for any given thread, the returned pointer shall always be the same.</span></div>
<div class="line"><a id="l00764" name="l00764"></a><span class="lineno">  764</span><span class="comment">   */</span></div>
<div class="line"><a id="l00765" name="l00765"></a><span class="lineno">  765</span>  <span class="keyword">static</span> <a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a>* <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a81da2c80d99cdd43c66a0df2eed64c70">this_thread_verbosity_override</a>();</div>
<div class="line"><a id="l00766" name="l00766"></a><span class="lineno">  766</span><span class="comment"></span> </div>
<div class="line"><a id="l00767" name="l00767"></a><span class="lineno">  767</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00768" name="l00768"></a><span class="lineno">  768</span><span class="comment">   * Sets `*(this_thread_verbosity_override()) = most_verbose_sev_or_none`; and returns an object that shall restore</span></div>
<div class="line"><a id="l00769" name="l00769"></a><span class="lineno">  769</span><span class="comment">   * it to its current value when it goes out of scope.  See class doc header for an example of use.</span></div>
<div class="line"><a id="l00770" name="l00770"></a><span class="lineno">  770</span><span class="comment">   *</span></div>
<div class="line"><a id="l00771" name="l00771"></a><span class="lineno">  771</span><span class="comment">   * It is recommended to use this method instead of direct assignment to the location this_thread_verbosity_override(),</span></div>
<div class="line"><a id="l00772" name="l00772"></a><span class="lineno">  772</span><span class="comment">   * as then it&#39;ll be auto-restored.</span></div>
<div class="line"><a id="l00773" name="l00773"></a><span class="lineno">  773</span><span class="comment">   *</span></div>
<div class="line"><a id="l00774" name="l00774"></a><span class="lineno">  774</span><span class="comment">   * @see this_thread_verbosity_override() and output_whether_should_log().</span></div>
<div class="line"><a id="l00775" name="l00775"></a><span class="lineno">  775</span><span class="comment">   *</span></div>
<div class="line"><a id="l00776" name="l00776"></a><span class="lineno">  776</span><span class="comment">   * @param most_verbose_sev_or_none</span></div>
<div class="line"><a id="l00777" name="l00777"></a><span class="lineno">  777</span><span class="comment">   *        A value suitable for configure_default_verbosity(); or the special value Sev::S_END_SENTINEL which</span></div>
<div class="line"><a id="l00778" name="l00778"></a><span class="lineno">  778</span><span class="comment">   *        disables the override (meaning `C.output_whether_should_log()` shall actually follow the config in `Config</span></div>
<div class="line"><a id="l00779" name="l00779"></a><span class="lineno">  779</span><span class="comment">   *        C` and not any override).</span></div>
<div class="line"><a id="l00780" name="l00780"></a><span class="lineno">  780</span><span class="comment">   * @return Object that, when it is destroyed, will restore the verbosity override to what it was before this</span></div>
<div class="line"><a id="l00781" name="l00781"></a><span class="lineno">  781</span><span class="comment">   *         call.  (The object cannot be copied, to prevent a double-restore.  It can however be moved-from.)</span></div>
<div class="line"><a id="l00782" name="l00782"></a><span class="lineno">  782</span><span class="comment">   */</span></div>
<div class="line"><a id="l00783" name="l00783"></a><span class="lineno">  783</span>  <span class="keyword">static</span> <a class="code hl_class" href="classflow_1_1util_1_1Scoped__setter.html">util::Scoped_setter&lt;Sev&gt;</a> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#ab025990297cc07d51aaec277af203dfe">this_thread_verbosity_override_auto</a>(<a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> most_verbose_sev_or_none);</div>
<div class="line"><a id="l00784" name="l00784"></a><span class="lineno">  784</span> </div>
<div class="line"><a id="l00785" name="l00785"></a><span class="lineno">  785</span>  <span class="comment">// Data.  (Public!)</span></div>
<div class="line"><a id="l00786" name="l00786"></a><span class="lineno">  786</span><span class="comment"></span> </div>
<div class="line"><a id="l00787" name="l00787"></a><span class="lineno">  787</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00788" name="l00788"></a><span class="lineno">  788</span><span class="comment">   * Config setting: If `true`, time stamps will include a (deterministically formatted) date, time, time zone, all in</span></div>
<div class="line"><a id="l00789" name="l00789"></a><span class="lineno">  789</span><span class="comment">   * the OS&#39;s current time zone; else raw # of seconds passed since POSIX (Unix) Epoch (1970, Jan 1, 00:00, GMT).</span></div>
<div class="line"><a id="l00790" name="l00790"></a><span class="lineno">  790</span><span class="comment">   * In both cases time is expressed with microsecond resolution (but the accuracy is only as good as the computer&#39;s</span></div>
<div class="line"><a id="l00791" name="l00791"></a><span class="lineno">  791</span><span class="comment">   * clock hardware and OS software allow, presumably, though this isn&#39;t in the purview of class Config).</span></div>
<div class="line"><a id="l00792" name="l00792"></a><span class="lineno">  792</span><span class="comment">   */</span></div>
<div class="line"><a id="l00793" name="l00793"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a1b16be31f5dcfba9536a377c9d29abb6">  793</a></span>  <span class="keywordtype">bool</span> <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a1b16be31f5dcfba9536a377c9d29abb6">m_use_human_friendly_time_stamps</a>;</div>
<div class="line"><a id="l00794" name="l00794"></a><span class="lineno">  794</span> </div>
<div class="line"><a id="l00795" name="l00795"></a><span class="lineno">  795</span><span class="keyword">private</span>:</div>
<div class="line"><a id="l00796" name="l00796"></a><span class="lineno">  796</span>  <span class="comment">// Types.</span></div>
<div class="line"><a id="l00797" name="l00797"></a><span class="lineno">  797</span><span class="comment"></span> </div>
<div class="line"><a id="l00798" name="l00798"></a><span class="lineno">  798</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00799" name="l00799"></a><span class="lineno">  799</span><span class="comment">   * The set of config stored for each distinct (as determined by Component::payload_type(), essentially</span></div>
<div class="line"><a id="l00800" name="l00800"></a><span class="lineno">  800</span><span class="comment">   * C++ built-in `std::type_info`) component payload type (in English -- component `enum class`).</span></div>
<div class="line"><a id="l00801" name="l00801"></a><span class="lineno">  801</span><span class="comment">   *</span></div>
<div class="line"><a id="l00802" name="l00802"></a><span class="lineno">  802</span><span class="comment">   * As I write this, there is only one member, so we did not need a `struct`, but it *really* felt like</span></div>
<div class="line"><a id="l00803" name="l00803"></a><span class="lineno">  803</span><span class="comment">   * it might get extended later -- and there is zero performance loss from this, and the extra code is minimal.</span></div>
<div class="line"><a id="l00804" name="l00804"></a><span class="lineno">  804</span><span class="comment">   */</span></div>
<div class="line"><a id="l00805" name="l00805"></a><span class="lineno"><a class="line" href="structflow_1_1log_1_1Config_1_1Component__config.html">  805</a></span>  <span class="keyword">struct </span><a class="code hl_struct" href="structflow_1_1log_1_1Config_1_1Component__config.html">Component_config</a></div>
<div class="line"><a id="l00806" name="l00806"></a><span class="lineno">  806</span>  {</div>
<div class="line"><a id="l00807" name="l00807"></a><span class="lineno">  807</span>    <span class="comment">// Data.</span></div>
<div class="line"><a id="l00808" name="l00808"></a><span class="lineno">  808</span><span class="comment"></span> </div>
<div class="line"><a id="l00809" name="l00809"></a><span class="lineno">  809</span><span class="comment">    /// See the `enum_to_num_offset` arg in init_component_to_union_idx_mapping() doc header.</span></div>
<div class="line"><a id="l00810" name="l00810"></a><span class="lineno"><a class="line" href="structflow_1_1log_1_1Config_1_1Component__config.html#af2e34d559da2d9d28cd744be5f8b6f07">  810</a></span><span class="comment"></span>    <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a> <a class="code hl_variable" href="structflow_1_1log_1_1Config_1_1Component__config.html#af2e34d559da2d9d28cd744be5f8b6f07">m_enum_to_num_offset</a>;</div>
<div class="line"><a id="l00811" name="l00811"></a><span class="lineno">  811</span>  };</div>
<div class="line"><a id="l00812" name="l00812"></a><span class="lineno">  812</span><span class="comment"></span> </div>
<div class="line"><a id="l00813" name="l00813"></a><span class="lineno">  813</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00814" name="l00814"></a><span class="lineno">  814</span><span class="comment">   * Short-hand for fast-lookup map from distinct `Component_payload` type to the config for that component `enum`.</span></div>
<div class="line"><a id="l00815" name="l00815"></a><span class="lineno">  815</span><span class="comment">   *</span></div>
<div class="line"><a id="l00816" name="l00816"></a><span class="lineno">  816</span><span class="comment">   * ### Rationale: Performance ###</span></div>
<div class="line"><a id="l00817" name="l00817"></a><span class="lineno">  817</span><span class="comment">   * First please see class log::Config doc header Performance section for user-facing perf recipe.  That is</span></div>
<div class="line"><a id="l00818" name="l00818"></a><span class="lineno">  818</span><span class="comment">   * related to this.  Then come back here.</span></div>
<div class="line"><a id="l00819" name="l00819"></a><span class="lineno">  819</span><span class="comment">   *</span></div>
<div class="line"><a id="l00820" name="l00820"></a><span class="lineno">  820</span><span class="comment">   * This is, conceptually, nothing more than a mapping from `std::type_info` (which comes from</span></div>
<div class="line"><a id="l00821" name="l00821"></a><span class="lineno">  821</span><span class="comment">   * `typeid(E)`, where `E` is the component `enum class` used for a given logging-module) to an array index</span></div>
<div class="line"><a id="l00822" name="l00822"></a><span class="lineno">  822</span><span class="comment">   * (more or less a `size_t`) -- where the size of the map is small: the number of logging-modules in your application.</span></div>
<div class="line"><a id="l00823" name="l00823"></a><span class="lineno">  823</span><span class="comment">   * (This is typically something like 1, 2, 3 -- almost certainly no higher than ~10.)  Each</span></div>
<div class="line"><a id="l00824" name="l00824"></a><span class="lineno">  824</span><span class="comment">   * init_component_to_union_idx_mapping() inserts a key-value pair.  Then each output_whether_should_log() -- of</span></div>
<div class="line"><a id="l00825" name="l00825"></a><span class="lineno">  825</span><span class="comment">   * which there will potentially be extremely many, one per log call site -- looks up a given key in this map.</span></div>
<div class="line"><a id="l00826" name="l00826"></a><span class="lineno">  826</span><span class="comment">   * (If found, it then looks up another key in a flat array.  That&#39;s irrelevant to our discussion here though.)</span></div>
<div class="line"><a id="l00827" name="l00827"></a><span class="lineno">  827</span><span class="comment">   *</span></div>
<div class="line"><a id="l00828" name="l00828"></a><span class="lineno">  828</span><span class="comment">   * Hence a naive impl (and indeed the original such impl) would just use the STL-recommended allegedly-fast</span></div>
<div class="line"><a id="l00829" name="l00829"></a><span class="lineno">  829</span><span class="comment">   * associative mapping from `type_index` (cted from `type_info`) to our integer value.  A classic move would</span></div>
<div class="line"><a id="l00830" name="l00830"></a><span class="lineno">  830</span><span class="comment">   * be to just use `unordered_map&lt;type_index, ...&gt;`: constant-time lookup, great!</span></div>
<div class="line"><a id="l00831" name="l00831"></a><span class="lineno">  831</span><span class="comment">   *</span></div>
<div class="line"><a id="l00832" name="l00832"></a><span class="lineno">  832</span><span class="comment">   * Unfortunately -- and this was borne out in a real project with real benchmarking -- that&#39;s not the case.</span></div>
<div class="line"><a id="l00833" name="l00833"></a><span class="lineno">  833</span><span class="comment">   * The reason: `type_index` (which stores `type_info*` internally) isn&#39;t all that fast really, because</span></div>
<div class="line"><a id="l00834" name="l00834"></a><span class="lineno">  834</span><span class="comment">   * hashing it cannot just hash the stored `type_info*` ptr value; and that is because 2 equal `type_info`s (referring</span></div>
<div class="line"><a id="l00835" name="l00835"></a><span class="lineno">  835</span><span class="comment">   * to the same type) *can* live at different addresses.  (When relevant `typeid()`s are invoked without a</span></div>
<div class="line"><a id="l00836" name="l00836"></a><span class="lineno">  836</span><span class="comment">   * shared-object boundary, they can&#39;t... but if dynamic linking is involved, then they can.)  Therefore</span></div>
<div class="line"><a id="l00837" name="l00837"></a><span class="lineno">  837</span><span class="comment">   * the hash of `type_index` has to use something else, and in fact this is usually `type_info::name()` which</span></div>
<div class="line"><a id="l00838" name="l00838"></a><span class="lineno">  838</span><span class="comment">   * is a fully qualified type name (in some interesting format, semi-readable usually).  That&#39;s a fairly expensive</span></div>
<div class="line"><a id="l00839" name="l00839"></a><span class="lineno">  839</span><span class="comment">   * operation that at least scans the entire string.  Using a sorted-map `std::map` does help -- the names can</span></div>
<div class="line"><a id="l00840" name="l00840"></a><span class="lineno">  840</span><span class="comment">   * be lexicographically compared which is faster, including many instances of early-return -- but still not amazing.</span></div>
<div class="line"><a id="l00841" name="l00841"></a><span class="lineno">  841</span><span class="comment">   *</span></div>
<div class="line"><a id="l00842" name="l00842"></a><span class="lineno">  842</span><span class="comment">   * That&#39;s why Component_payload_type_dict (and its buddies) exists as opposed to just using a straightforward</span></div>
<div class="line"><a id="l00843" name="l00843"></a><span class="lineno">  843</span><span class="comment">   * hash-map.  We wrote some code that uses `type_info*` pointer values after all, when possible</span></div>
<div class="line"><a id="l00844" name="l00844"></a><span class="lineno">  844</span><span class="comment">   * (and hence the `component_payload_type_info_ptr_is_uniq` hint arg to init_component_to_union_idx_mapping()).</span></div>
<div class="line"><a id="l00845" name="l00845"></a><span class="lineno">  845</span><span class="comment">   * Further details are encapsulated in Component_payload_type_dict land.</span></div>
<div class="line"><a id="l00846" name="l00846"></a><span class="lineno">  846</span><span class="comment">   *</span></div>
<div class="line"><a id="l00847" name="l00847"></a><span class="lineno">  847</span><span class="comment">   * So what one needs to decide here is how to configure Component_payload_type_dict via its two template args</span></div>
<div class="line"><a id="l00848" name="l00848"></a><span class="lineno">  848</span><span class="comment">   * just below.  The current choices were obtained empirically with benchmarking (which can be found elsewhere</span></div>
<div class="line"><a id="l00849" name="l00849"></a><span class="lineno">  849</span><span class="comment">   * in unit-test-land; a unit test will fail if those benchmarks start giving very unexpected results, e.g. due</span></div>
<div class="line"><a id="l00850" name="l00850"></a><span class="lineno">  850</span><span class="comment">   * to differing hardware or who knows what). (See #FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_PTR and</span></div>
<div class="line"><a id="l00851" name="l00851"></a><span class="lineno">  851</span><span class="comment">   * #FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_VAL Impl section for discussion.  These also allow</span></div>
<div class="line"><a id="l00852" name="l00852"></a><span class="lineno">  852</span><span class="comment">   * user to override all or part of our decision.)</span></div>
<div class="line"><a id="l00853" name="l00853"></a><span class="lineno">  853</span><span class="comment">   */</span></div>
<div class="line"><a id="l00854" name="l00854"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#aab7de884a6d86042404dd1cb04691f02">  854</a></span>  <span class="keyword">using </span><a class="code hl_class" href="classflow_1_1log_1_1Component__payload__type__dict.html">Component_payload_type_to_cfg_map</a></div>
<div class="line"><a id="l00855" name="l00855"></a><span class="lineno">  855</span>    = <a class="code hl_class" href="classflow_1_1log_1_1Component__payload__type__dict.html">Component_payload_type_dict&lt;FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_PTR&lt;Component_config&gt;</a>,</div>
<div class="line"><a id="l00856" name="l00856"></a><span class="lineno">  856</span>                                  FLOW_LOG_CONFIG_COMPONENT_PAYLOAD_TYPE_DICT_BY_VAL&lt;Component_config&gt;&gt;;</div>
<div class="line"><a id="l00857" name="l00857"></a><span class="lineno">  857</span><span class="comment"></span> </div>
<div class="line"><a id="l00858" name="l00858"></a><span class="lineno">  858</span><span class="comment">  /// How we store a log::Sev (a mere `enum` itself) in a certain data structure.</span></div>
<div class="line"><a id="l00859" name="l00859"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#acae76e3367bd497f5b00f46e48b3a39c">  859</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#acae76e3367bd497f5b00f46e48b3a39c">raw_sev_t</a> = <a class="code hl_typedef" href="namespaceflow.html#ae02da22c4a101eaab447511c905e4f32">uint8_t</a>;</div>
<div class="line"><a id="l00860" name="l00860"></a><span class="lineno">  860</span><span class="comment"></span> </div>
<div class="line"><a id="l00861" name="l00861"></a><span class="lineno">  861</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00862" name="l00862"></a><span class="lineno">  862</span><span class="comment">   * Trivial wrapper of `atomic&lt;raw_sev_t&gt;` which adds a couple of things to make it possible to construct, and</span></div>
<div class="line"><a id="l00863" name="l00863"></a><span class="lineno">  863</span><span class="comment">   * therefore use, a `vector` of such `atomic`s.</span></div>
<div class="line"><a id="l00864" name="l00864"></a><span class="lineno">  864</span><span class="comment">   *</span></div>
<div class="line"><a id="l00865" name="l00865"></a><span class="lineno">  865</span><span class="comment">   * The primary reason it exists is that it&#39;s not possible to `push_back()` (and therefore `resize()`) or surprisingly</span></div>
<div class="line"><a id="l00866" name="l00866"></a><span class="lineno">  866</span><span class="comment">   * even `reserve()` (hence `emplace_back()` is also impossible) onto a `vector&lt;atomic&lt;&gt;&gt;`.  A copy constructor</span></div>
<div class="line"><a id="l00867" name="l00867"></a><span class="lineno">  867</span><span class="comment">   * is required.  Without one, I (ygoldfel) was able to *almost* get it to build, except it turns out that even</span></div>
<div class="line"><a id="l00868" name="l00868"></a><span class="lineno">  868</span><span class="comment">   * `reserve()` (which essentially is required for anything that grows the sequence) needs to be able to copy</span></div>
<div class="line"><a id="l00869" name="l00869"></a><span class="lineno">  869</span><span class="comment">   * `atomic&lt;&gt;`s -- albeit uninitialized ones -- even if one plans to construct in-place via `emplace_back()` (etc.).</span></div>
<div class="line"><a id="l00870" name="l00870"></a><span class="lineno">  870</span><span class="comment">   * We hence provide a copy constructor ourselves in the wrapper; but note that it has certain stringent requirements</span></div>
<div class="line"><a id="l00871" name="l00871"></a><span class="lineno">  871</span><span class="comment">   * for safe use; see its doc header.</span></div>
<div class="line"><a id="l00872" name="l00872"></a><span class="lineno">  872</span><span class="comment">   *</span></div>
<div class="line"><a id="l00873" name="l00873"></a><span class="lineno">  873</span><span class="comment">   * A side nicety is we can set the default constructor to, instead of keeping the value unspecified (probably</span></div>
<div class="line"><a id="l00874" name="l00874"></a><span class="lineno">  874</span><span class="comment">   * uninitialized but definitely resulting in a valid object), init it to our special value `raw_sev_t(-1)`, which</span></div>
<div class="line"><a id="l00875" name="l00875"></a><span class="lineno">  875</span><span class="comment">   * is used in Config::Component_union_idx_to_sev_map to represent the concept &quot;index-not-in-map.&quot;  That&#39;s mere</span></div>
<div class="line"><a id="l00876" name="l00876"></a><span class="lineno">  876</span><span class="comment">   * syntactic sugar, but it works for us.</span></div>
<div class="line"><a id="l00877" name="l00877"></a><span class="lineno">  877</span><span class="comment">   *</span></div>
<div class="line"><a id="l00878" name="l00878"></a><span class="lineno">  878</span><span class="comment">   * @see I (ygoldfel) discovered and solved this all myself when trying to compile; but it&#39;s a generally easily</span></div>
<div class="line"><a id="l00879" name="l00879"></a><span class="lineno">  879</span><span class="comment">   *      Googlable situation and solution (that confirmed my findings); e.g.:</span></div>
<div class="line"><a id="l00880" name="l00880"></a><span class="lineno">  880</span><span class="comment">   *      https://stackoverflow.com/questions/12003024/error-with-copy-constructor-assignment-operator-for-a-class-which-has-stdatomi</span></div>
<div class="line"><a id="l00881" name="l00881"></a><span class="lineno">  881</span><span class="comment">   */</span></div>
<div class="line"><a id="l00882" name="l00882"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html">  882</a></span>  <span class="keyword">class </span><a class="code hl_class" href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html">Atomic_raw_sev</a> : <span class="keyword">public</span> std::atomic&lt;raw_sev_t&gt;</div>
<div class="line"><a id="l00883" name="l00883"></a><span class="lineno">  883</span>  {</div>
<div class="line"><a id="l00884" name="l00884"></a><span class="lineno">  884</span>  <span class="keyword">public</span>:</div>
<div class="line"><a id="l00885" name="l00885"></a><span class="lineno">  885</span>    <span class="comment">// Constructor/destructor.</span></div>
<div class="line"><a id="l00886" name="l00886"></a><span class="lineno">  886</span><span class="comment"></span> </div>
<div class="line"><a id="l00887" name="l00887"></a><span class="lineno">  887</span><span class="comment">    /**</span></div>
<div class="line"><a id="l00888" name="l00888"></a><span class="lineno">  888</span><span class="comment">     * Constructs the atomic to the given value, guaranteed to be `load()`ed as such in all subsequent accesses incl</span></div>
<div class="line"><a id="l00889" name="l00889"></a><span class="lineno">  889</span><span class="comment">     * from other threads, even if `memory_order_relaxed` is used.</span></div>
<div class="line"><a id="l00890" name="l00890"></a><span class="lineno">  890</span><span class="comment">     *</span></div>
<div class="line"><a id="l00891" name="l00891"></a><span class="lineno">  891</span><span class="comment">     * @param init_val</span></div>
<div class="line"><a id="l00892" name="l00892"></a><span class="lineno">  892</span><span class="comment">     *        The value whose copy to set as the payload of this `atomic&lt;&gt;`.</span></div>
<div class="line"><a id="l00893" name="l00893"></a><span class="lineno">  893</span><span class="comment">     */</span></div>
<div class="line"><a id="l00894" name="l00894"></a><span class="lineno">  894</span>    <a class="code hl_function" href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html#a0edf54321d64532405b9786dd707e026">Atomic_raw_sev</a>(<a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#acae76e3367bd497f5b00f46e48b3a39c">raw_sev_t</a> init_val = <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#acae76e3367bd497f5b00f46e48b3a39c">raw_sev_t</a>(-1));</div>
<div class="line"><a id="l00895" name="l00895"></a><span class="lineno">  895</span><span class="comment"></span> </div>
<div class="line"><a id="l00896" name="l00896"></a><span class="lineno">  896</span><span class="comment">    /**</span></div>
<div class="line"><a id="l00897" name="l00897"></a><span class="lineno">  897</span><span class="comment">     * Constructs the atomic to hold the value X held by the given other atomic accoding to a `memory_order_relaxed`</span></div>
<div class="line"><a id="l00898" name="l00898"></a><span class="lineno">  898</span><span class="comment">     * load of the latter.</span></div>
<div class="line"><a id="l00899" name="l00899"></a><span class="lineno">  899</span><span class="comment">     *</span></div>
<div class="line"><a id="l00900" name="l00900"></a><span class="lineno">  900</span><span class="comment">     * There is a subtlety: One generally expects that a just-constructed `atomic&lt;&gt; X(a)` must yield</span></div>
<div class="line"><a id="l00901" name="l00901"></a><span class="lineno">  901</span><span class="comment">     * `X.load(memory_order_relaxed) == a` no mater the thread where the load is done or how soon after construction.</span></div>
<div class="line"><a id="l00902" name="l00902"></a><span class="lineno">  902</span><span class="comment">     * Yet the present ctor by definition essentially performs `atomic&lt;&gt; X(src.load(memory_order_relaxed))`, hence</span></div>
<div class="line"><a id="l00903" name="l00903"></a><span class="lineno">  903</span><span class="comment">     * the subtlety: The `src.load()` needs to return the &quot;true&quot; value intended to be stored inside `src`, not some</span></div>
<div class="line"><a id="l00904" name="l00904"></a><span class="lineno">  904</span><span class="comment">     * cached/whatever older value in the current thread.  One way to guarantee this is to both construct (and</span></div>
<div class="line"><a id="l00905" name="l00905"></a><span class="lineno">  905</span><span class="comment">     * optionally modify) `src` *only* in the present thread before calling the present ctor.</span></div>
<div class="line"><a id="l00906" name="l00906"></a><span class="lineno">  906</span><span class="comment">     *</span></div>
<div class="line"><a id="l00907" name="l00907"></a><span class="lineno">  907</span><span class="comment">     * Be very careful to ensure you&#39;ve considered this when copy-contructing.</span></div>
<div class="line"><a id="l00908" name="l00908"></a><span class="lineno">  908</span><span class="comment">     * Otherwise, it will probably work the *vast* majority of the</span></div>
<div class="line"><a id="l00909" name="l00909"></a><span class="lineno">  909</span><span class="comment">     * time; yet it may silently result in `this-&gt;load(memory_order_relaxed)` returning some unexpected value,</span></div>
<div class="line"><a id="l00910" name="l00910"></a><span class="lineno">  910</span><span class="comment">     * depending on whether the &quot;master&quot; value of `src` has propagated to the present thread.  Formally speaking</span></div>
<div class="line"><a id="l00911" name="l00911"></a><span class="lineno">  911</span><span class="comment">     * behavior is undefined outside of the aforementioned condition.  In actual fact, we do guarantee this</span></div>
<div class="line"><a id="l00912" name="l00912"></a><span class="lineno">  912</span><span class="comment">     * when growing Config::m_verbosities_by_component; and the other call site is the `default`</span></div>
<div class="line"><a id="l00913" name="l00913"></a><span class="lineno">  913</span><span class="comment">     * Config copy constructor/etc., whose doc header mentions this limitation.</span></div>
<div class="line"><a id="l00914" name="l00914"></a><span class="lineno">  914</span><span class="comment">     *</span></div>
<div class="line"><a id="l00915" name="l00915"></a><span class="lineno">  915</span><span class="comment">     * @param src</span></div>
<div class="line"><a id="l00916" name="l00916"></a><span class="lineno">  916</span><span class="comment">     *        Other object.  Behavior undefined if `(this == &amp;src)`.</span></div>
<div class="line"><a id="l00917" name="l00917"></a><span class="lineno">  917</span><span class="comment">     */</span></div>
<div class="line"><a id="l00918" name="l00918"></a><span class="lineno">  918</span>    <a class="code hl_function" href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html#a0edf54321d64532405b9786dd707e026">Atomic_raw_sev</a>(<span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html">Atomic_raw_sev</a>&amp; src);</div>
<div class="line"><a id="l00919" name="l00919"></a><span class="lineno">  919</span>  }; <span class="comment">// class Atomic_raw_sev</span></div>
<div class="line"><a id="l00920" name="l00920"></a><span class="lineno">  920</span><span class="comment"></span> </div>
<div class="line"><a id="l00921" name="l00921"></a><span class="lineno">  921</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00922" name="l00922"></a><span class="lineno">  922</span><span class="comment">   * Short-hand for fast-lookup, thread-safe-for-RW mapping from flat-union-component-table index to max</span></div>
<div class="line"><a id="l00923" name="l00923"></a><span class="lineno">  923</span><span class="comment">   * allowed severity for that component.</span></div>
<div class="line"><a id="l00924" name="l00924"></a><span class="lineno">  924</span><span class="comment">   *</span></div>
<div class="line"><a id="l00925" name="l00925"></a><span class="lineno">  925</span><span class="comment">   * ### Rationale ###</span></div>
<div class="line"><a id="l00926" name="l00926"></a><span class="lineno">  926</span><span class="comment">   * 2 things will jump out at many readers: 1: It is a `vector`, instead of the seemingly more elegant and essentially</span></div>
<div class="line"><a id="l00927" name="l00927"></a><span class="lineno">  927</span><span class="comment">   * as-fast `unordered_map&lt;component_union_idx_t, Sev&gt;`. 2: It stores `atomic&lt;raw_sev_t&gt;` and not simply `Sev`.</span></div>
<div class="line"><a id="l00928" name="l00928"></a><span class="lineno">  928</span><span class="comment">   * The reason for both is thread safety, to wit for 2 operations: writing to it via</span></div>
<div class="line"><a id="l00929" name="l00929"></a><span class="lineno">  929</span><span class="comment">   * `configure_component_verbosity*()` vs. reading from it in output_whether_should_log().</span></div>
<div class="line"><a id="l00930" name="l00930"></a><span class="lineno">  930</span><span class="comment">   * In one makes the two mutually safe for concurrent execution in a given `*this`, it becomes possible to safely</span></div>
<div class="line"><a id="l00931" name="l00931"></a><span class="lineno">  931</span><span class="comment">   * configure per-component verbosity even while the rest of the system is concurrently logging like crazy.</span></div>
<div class="line"><a id="l00932" name="l00932"></a><span class="lineno">  932</span><span class="comment">   * So how does this type accomplish that?  Tackling the 2 decisions in order:</span></div>
<div class="line"><a id="l00933" name="l00933"></a><span class="lineno">  933</span><span class="comment">   *</span></div>
<div class="line"><a id="l00934" name="l00934"></a><span class="lineno">  934</span><span class="comment">   * Firstly assume for simplicity that `component_union_idx_t` is `size_t`; and that `Sev` and `raw_sev_t` are</span></div>
<div class="line"><a id="l00935" name="l00935"></a><span class="lineno">  935</span><span class="comment">   * essentially the same thing (enough so for this discussion anyway).</span></div>
<div class="line"><a id="l00936" name="l00936"></a><span class="lineno">  936</span><span class="comment">   * Now consider an `X` of this map type.  If it were a `..._map&lt;size_t, ...&gt;`, then `X[A] = B;` might change the</span></div>
<div class="line"><a id="l00937" name="l00937"></a><span class="lineno">  937</span><span class="comment">   * internal structure of the map (hash table, tree, whatever); accessing `X[C]` for *any* `C` would not be safe, as</span></div>
<div class="line"><a id="l00938" name="l00938"></a><span class="lineno">  938</span><span class="comment">   * it could catch it in a halfway state among other dangers.  If it is a `vector&lt;...&gt;`, however, then</span></div>
<div class="line"><a id="l00939" name="l00939"></a><span class="lineno">  939</span><span class="comment">   * `X[A] = B;` either results in undefined-behavior -- if `X.size() &gt;= A` -- or works fine, in that the buffer inside</span></div>
<div class="line"><a id="l00940" name="l00940"></a><span class="lineno">  940</span><span class="comment">   * `X` does not change structure.  (However, this does indeed require that `X` is sized to allow for all possible</span></div>
<div class="line"><a id="l00941" name="l00941"></a><span class="lineno">  941</span><span class="comment">   * values of `A`.  It also makes `X` sparse and hence larger than it otherwise would require.  The latter is seen</span></div>
<div class="line"><a id="l00942" name="l00942"></a><span class="lineno">  942</span><span class="comment">   * as likely negligible given the number of components used in reality vs. how much RAM modern computers have;</span></div>
<div class="line"><a id="l00943" name="l00943"></a><span class="lineno">  943</span><span class="comment">   * to shrink it further and improve the set-all operation&#39;s speed is why we use single-byte `raw_sev_t` and not `Sev`.</span></div>
<div class="line"><a id="l00944" name="l00944"></a><span class="lineno">  944</span><span class="comment">   * As for pre-sizing, that explains the need for init_component_to_union_idx_mapping() arg `enum_sparse_length`.</span></div>
<div class="line"><a id="l00945" name="l00945"></a><span class="lineno">  945</span><span class="comment">   * TL;DR: It makes it so that the address in the reference `X[A]` never changes for a given `A`, as long as no</span></div>
<div class="line"><a id="l00946" name="l00946"></a><span class="lineno">  946</span><span class="comment">   * `resize()` or equivalent occurs throughout.</span></div>
<div class="line"><a id="l00947" name="l00947"></a><span class="lineno">  947</span><span class="comment">   *</span></div>
<div class="line"><a id="l00948" name="l00948"></a><span class="lineno">  948</span><span class="comment">   * Given that, why `atomic&lt;raw_sev_t&gt;` and not `raw_sev_t` alone?  Well, even though `X[A]` address never changes</span></div>
<div class="line"><a id="l00949" name="l00949"></a><span class="lineno">  949</span><span class="comment">   * and is thus thread-safe at the `X` level, the `= B;` assignment itself isn&#39;t thread-safe against reading the value.</span></div>
<div class="line"><a id="l00950" name="l00950"></a><span class="lineno">  950</span><span class="comment">   * Now, the extent to which it&#39;s not &quot;thread-safe&quot; depends on hairy low-level details; wrapping it in</span></div>
<div class="line"><a id="l00951" name="l00951"></a><span class="lineno">  951</span><span class="comment">   * `atomic&lt;&gt;` allows one to explicitly control the level of thread safety and the associated performance trade-off</span></div>
<div class="line"><a id="l00952" name="l00952"></a><span class="lineno">  952</span><span class="comment">   * (potentially significant since output_whether_should_log() is called at every single log call site).</span></div>
<div class="line"><a id="l00953" name="l00953"></a><span class="lineno">  953</span><span class="comment">   * With `atomic&lt;&gt;` one can use `memory_order` specifications when storing and reading to control this.</span></div>
<div class="line"><a id="l00954" name="l00954"></a><span class="lineno">  954</span><span class="comment">   * Further details are discussed at the read and write sites, but that&#39;s why `atomic&lt;&gt;` is used.</span></div>
<div class="line"><a id="l00955" name="l00955"></a><span class="lineno">  955</span><span class="comment">   *</span></div>
<div class="line"><a id="l00956" name="l00956"></a><span class="lineno">  956</span><span class="comment">   * ### Why the wrapper Atomic_raw_sev around the `atomic&lt;&gt;`? ###</span></div>
<div class="line"><a id="l00957" name="l00957"></a><span class="lineno">  957</span><span class="comment">   * Short version: It&#39;s because `vector&lt;&gt;` effectively cannot be initialized due to `atomic&lt;&gt;` not being</span></div>
<div class="line"><a id="l00958" name="l00958"></a><span class="lineno">  958</span><span class="comment">   * copy-constructible.  (However Atomic_raw_sev, after construction, is identical to `atomic&lt;raw_sev_t&gt;`, effectively</span></div>
<div class="line"><a id="l00959" name="l00959"></a><span class="lineno">  959</span><span class="comment">   * a `using`-alias at that point.)  Long version: See doc header for Atomic_raw_sev.</span></div>
<div class="line"><a id="l00960" name="l00960"></a><span class="lineno">  960</span><span class="comment">   *</span></div>
<div class="line"><a id="l00961" name="l00961"></a><span class="lineno">  961</span><span class="comment">   * ### Performance ###</span></div>
<div class="line"><a id="l00962" name="l00962"></a><span class="lineno">  962</span><span class="comment">   * The lookup by index could not be any faster: it adds the index to a base integer and done.  This is even somewhat</span></div>
<div class="line"><a id="l00963" name="l00963"></a><span class="lineno">  963</span><span class="comment">   * faster than an `unordered_map&lt;&gt;` which is also constant-time but a bit more involved.  The writing and reading</span></div>
<div class="line"><a id="l00964" name="l00964"></a><span class="lineno">  964</span><span class="comment">   * of the `atomic&lt;&gt;` can be faster than with an explicit mutex lock/unlock bracketing but can be somewhat slower than</span></div>
<div class="line"><a id="l00965" name="l00965"></a><span class="lineno">  965</span><span class="comment">   * an unprotected assignment/read; or it can be exactly equal; the point is that is under our control</span></div>
<div class="line"><a id="l00966" name="l00966"></a><span class="lineno">  966</span><span class="comment">   * via `memory_order` spec; again, see details at the read and write sites.</span></div>
<div class="line"><a id="l00967" name="l00967"></a><span class="lineno">  967</span><span class="comment">   */</span></div>
<div class="line"><a id="l00968" name="l00968"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a3c5c7d62daba9625b0309b31da287585">  968</a></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#a3c5c7d62daba9625b0309b31da287585">Component_union_idx_to_sev_map</a> = std::vector&lt;Atomic_raw_sev&gt;;</div>
<div class="line"><a id="l00969" name="l00969"></a><span class="lineno">  969</span> </div>
<div class="line"><a id="l00970" name="l00970"></a><span class="lineno">  970</span>  <span class="comment">/* Ensure it&#39;s fine to use `vector` index (`size_t` by definition) as a conceptual equivalent of a</span></div>
<div class="line"><a id="l00971" name="l00971"></a><span class="lineno">  971</span><span class="comment">   * `component_union_idx_t` key in a map. */</span></div>
<div class="line"><a id="l00972" name="l00972"></a><span class="lineno">  972</span>  <span class="keyword">static_assert</span>(std::numeric_limits&lt;component_union_idx_t&gt;::is_integer</div>
<div class="line"><a id="l00973" name="l00973"></a><span class="lineno">  973</span>                  &amp;&amp; (!std::numeric_limits&lt;component_union_idx_t&gt;::is_signed)</div>
<div class="line"><a id="l00974" name="l00974"></a><span class="lineno">  974</span>                  &amp;&amp; (!std::numeric_limits&lt;size_t&gt;::is_signed)</div>
<div class="line"><a id="l00975" name="l00975"></a><span class="lineno">  975</span>                  &amp;&amp; (<span class="keyword">sizeof</span>(size_t) &gt;= <span class="keyword">sizeof</span>(<a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a>)),</div>
<div class="line"><a id="l00976" name="l00976"></a><span class="lineno">  976</span>                <span class="stringliteral">&quot;size_t must be able to act as equivalent to a component_union_idx_t key.&quot;</span>);</div>
<div class="line"><a id="l00977" name="l00977"></a><span class="lineno">  977</span><span class="comment"></span> </div>
<div class="line"><a id="l00978" name="l00978"></a><span class="lineno">  978</span><span class="comment">  /// Short-hand for fast-lookup map from normalized component name to its flat-union-component-table index.</span></div>
<div class="line"><a id="l00979" name="l00979"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#aa1ed54fc7cef5b0ba4eadf97daf79be7">  979</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aa1ed54fc7cef5b0ba4eadf97daf79be7">Component_name_to_union_idx_map</a> = boost::unordered_map&lt;std::string, component_union_idx_t&gt;;</div>
<div class="line"><a id="l00980" name="l00980"></a><span class="lineno">  980</span><span class="comment"></span> </div>
<div class="line"><a id="l00981" name="l00981"></a><span class="lineno">  981</span><span class="comment">  /// Short-hand for map that is essentially the inverse of `Component_name_to_union_idx_map`.</span></div>
<div class="line"><a id="l00982" name="l00982"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a663307a81245b621e12680d3a4d83df2">  982</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#a663307a81245b621e12680d3a4d83df2">Component_union_idx_to_name_map</a> = boost::unordered_map&lt;component_union_idx_t, std::string&gt;;</div>
<div class="line"><a id="l00983" name="l00983"></a><span class="lineno">  983</span> </div>
<div class="line"><a id="l00984" name="l00984"></a><span class="lineno">  984</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00985" name="l00985"></a><span class="lineno">  985</span><span class="comment"></span> </div>
<div class="line"><a id="l00986" name="l00986"></a><span class="lineno">  986</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00987" name="l00987"></a><span class="lineno">  987</span><span class="comment">   * Normalized version of given component name.</span></div>
<div class="line"><a id="l00988" name="l00988"></a><span class="lineno">  988</span><span class="comment">   *</span></div>
<div class="line"><a id="l00989" name="l00989"></a><span class="lineno">  989</span><span class="comment">   * @param name</span></div>
<div class="line"><a id="l00990" name="l00990"></a><span class="lineno">  990</span><span class="comment">   *        Source name.</span></div>
<div class="line"><a id="l00991" name="l00991"></a><span class="lineno">  991</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00992" name="l00992"></a><span class="lineno">  992</span><span class="comment">   */</span></div>
<div class="line"><a id="l00993" name="l00993"></a><span class="lineno">  993</span>  <span class="keyword">static</span> std::string <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a428c0ae690c951c1667e24afb6ef43de">normalized_component_name</a>(<a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> name);</div>
<div class="line"><a id="l00994" name="l00994"></a><span class="lineno">  994</span><span class="comment"></span> </div>
<div class="line"><a id="l00995" name="l00995"></a><span class="lineno">  995</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00996" name="l00996"></a><span class="lineno">  996</span><span class="comment">   * Normalizes given component name in place.</span></div>
<div class="line"><a id="l00997" name="l00997"></a><span class="lineno">  997</span><span class="comment">   *</span></div>
<div class="line"><a id="l00998" name="l00998"></a><span class="lineno">  998</span><span class="comment">   * @param name</span></div>
<div class="line"><a id="l00999" name="l00999"></a><span class="lineno">  999</span><span class="comment">   *        Pointer (not null) to string to potentially modify.</span></div>
<div class="line"><a id="l01000" name="l01000"></a><span class="lineno"> 1000</span><span class="comment">   */</span></div>
<div class="line"><a id="l01001" name="l01001"></a><span class="lineno"> 1001</span>  <span class="keyword">static</span> <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a2a7be5337621d131ef084ba69ad95f1b">normalize_component_name</a>(std::string* name);</div>
<div class="line"><a id="l01002" name="l01002"></a><span class="lineno"> 1002</span><span class="comment"></span> </div>
<div class="line"><a id="l01003" name="l01003"></a><span class="lineno"> 1003</span><span class="comment">  /**</span></div>
<div class="line"><a id="l01004" name="l01004"></a><span class="lineno"> 1004</span><span class="comment">   * Given a component in the form user provides it at log call sites, returns its index in the flat component union</span></div>
<div class="line"><a id="l01005" name="l01005"></a><span class="lineno"> 1005</span><span class="comment">   * table, as registered via init_component_to_union_idx_mapping(); or `component_union_idx_t(-1)` if</span></div>
<div class="line"><a id="l01006" name="l01006"></a><span class="lineno"> 1006</span><span class="comment">   * `component.payload_type()` was not registed.</span></div>
<div class="line"><a id="l01007" name="l01007"></a><span class="lineno"> 1007</span><span class="comment">   *</span></div>
<div class="line"><a id="l01008" name="l01008"></a><span class="lineno"> 1008</span><span class="comment">   * @param component</span></div>
<div class="line"><a id="l01009" name="l01009"></a><span class="lineno"> 1009</span><span class="comment">   *        A Component value as from a log call site.  Undefined behavior if `component.empty()` (null Component).</span></div>
<div class="line"><a id="l01010" name="l01010"></a><span class="lineno"> 1010</span><span class="comment">   * @return Index into the flat component union table (0 or higher); or `component_union_idx_t(-1)`.  See above.</span></div>
<div class="line"><a id="l01011" name="l01011"></a><span class="lineno"> 1011</span><span class="comment">   */</span></div>
<div class="line"><a id="l01012" name="l01012"></a><span class="lineno"> 1012</span>  <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#af2d963a6e1e9e0fc5809764d5718e938">component_to_union_idx</a>(<span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1log_1_1Component.html">Component</a>&amp; component) <span class="keyword">const</span>;</div>
<div class="line"><a id="l01013" name="l01013"></a><span class="lineno"> 1013</span><span class="comment"></span> </div>
<div class="line"><a id="l01014" name="l01014"></a><span class="lineno"> 1014</span><span class="comment">  /**</span></div>
<div class="line"><a id="l01015" name="l01015"></a><span class="lineno"> 1015</span><span class="comment">   * Helper that for the given flat-union-component-index saves the given per-component verbosity, or removes it.</span></div>
<div class="line"><a id="l01016" name="l01016"></a><span class="lineno"> 1016</span><span class="comment">   *</span></div>
<div class="line"><a id="l01017" name="l01017"></a><span class="lineno"> 1017</span><span class="comment">   * @param component_union_idx</span></div>
<div class="line"><a id="l01018" name="l01018"></a><span class="lineno"> 1018</span><span class="comment">   *        Index into #m_verbosities_by_component.  -1 leads to undefined behavior.  Out-of-bounds leads to undefined</span></div>
<div class="line"><a id="l01019" name="l01019"></a><span class="lineno"> 1019</span><span class="comment">   *        behavior.  For rationale for the latter decision see doc header for #m_verbosities_by_component.</span></div>
<div class="line"><a id="l01020" name="l01020"></a><span class="lineno"> 1020</span><span class="comment">   * @param most_verbose_sev_or_none</span></div>
<div class="line"><a id="l01021" name="l01021"></a><span class="lineno"> 1021</span><span class="comment">   *        Either a cast of a valid log::Sev value indicating the most-verbose (highest) severity allowed to</span></div>
<div class="line"><a id="l01022" name="l01022"></a><span class="lineno"> 1022</span><span class="comment">   *        pass the output_whether_should_log() filter; or -1 to remove the per-component verbosity.</span></div>
<div class="line"><a id="l01023" name="l01023"></a><span class="lineno"> 1023</span><span class="comment">   *        Note that `Sev::S_NONE` is valid in this context and would disable all logging for that component.</span></div>
<div class="line"><a id="l01024" name="l01024"></a><span class="lineno"> 1024</span><span class="comment">   *        Conversely -1 would mean the component is removed from the conceptual &quot;map.&quot;</span></div>
<div class="line"><a id="l01025" name="l01025"></a><span class="lineno"> 1025</span><span class="comment">   */</span></div>
<div class="line"><a id="l01026" name="l01026"></a><span class="lineno"> 1026</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#aee6877cec4b070e18a40090f080e76ca">store_severity_by_component</a>(<a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a> component_union_idx, <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#acae76e3367bd497f5b00f46e48b3a39c">raw_sev_t</a> most_verbose_sev_or_none);</div>
<div class="line"><a id="l01027" name="l01027"></a><span class="lineno"> 1027</span> </div>
<div class="line"><a id="l01028" name="l01028"></a><span class="lineno"> 1028</span>  <span class="comment">// Data.</span></div>
<div class="line"><a id="l01029" name="l01029"></a><span class="lineno"> 1029</span><span class="comment"></span> </div>
<div class="line"><a id="l01030" name="l01030"></a><span class="lineno"> 1030</span><span class="comment">  /**</span></div>
<div class="line"><a id="l01031" name="l01031"></a><span class="lineno"> 1031</span><span class="comment">   * Fast-lookup map from distinct `Component_payload` type to the config for that component `enum`.</span></div>
<div class="line"><a id="l01032" name="l01032"></a><span class="lineno"> 1032</span><span class="comment">   * The key is `std::type_info`, a/k/a Component::payload_type().</span></div>
<div class="line"><a id="l01033" name="l01033"></a><span class="lineno"> 1033</span><span class="comment">   */</span></div>
<div class="line"><a id="l01034" name="l01034"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#ae447f7751eb63baefb04fdeeeff95fda"> 1034</a></span>  <a class="code hl_class" href="classflow_1_1log_1_1Component__payload__type__dict.html">Component_payload_type_to_cfg_map</a> <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#ae447f7751eb63baefb04fdeeeff95fda">m_component_cfgs_by_payload_type</a>;</div>
<div class="line"><a id="l01035" name="l01035"></a><span class="lineno"> 1035</span><span class="comment"></span> </div>
<div class="line"><a id="l01036" name="l01036"></a><span class="lineno"> 1036</span><span class="comment">  /**</span></div>
<div class="line"><a id="l01037" name="l01037"></a><span class="lineno"> 1037</span><span class="comment">   * Most verbose (highest) log::Sev for which output_whether_should_log() will return true, when the input</span></div>
<div class="line"><a id="l01038" name="l01038"></a><span class="lineno"> 1038</span><span class="comment">   * component is null or lacks a per-component configured verbosity.  Note that some log systems will choose to</span></div>
<div class="line"><a id="l01039" name="l01039"></a><span class="lineno"> 1039</span><span class="comment">   * use only this and not even allow any elements in #m_verbosities_by_component (see its doc header for definition</span></div>
<div class="line"><a id="l01040" name="l01040"></a><span class="lineno"> 1040</span><span class="comment">   * of containing or lacking an element).</span></div>
<div class="line"><a id="l01041" name="l01041"></a><span class="lineno"> 1041</span><span class="comment">   *</span></div>
<div class="line"><a id="l01042" name="l01042"></a><span class="lineno"> 1042</span><span class="comment">   * ### Rationale: Why Atomic_raw_sev instead of just log::Sev? ###</span></div>
<div class="line"><a id="l01043" name="l01043"></a><span class="lineno"> 1043</span><span class="comment">   * The reasoning is identical to that found in the discussion of why `atomic` is used in</span></div>
<div class="line"><a id="l01044" name="l01044"></a><span class="lineno"> 1044</span><span class="comment">   * #Component_union_idx_to_sev_map; see its doc header.  (We don&#39;t have to store a #raw_sev_t, as it&#39;s one lousy value</span></div>
<div class="line"><a id="l01045" name="l01045"></a><span class="lineno"> 1045</span><span class="comment">   * and not a bulk container in this case, but we do anyway just to get the copyability for free without having</span></div>
<div class="line"><a id="l01046" name="l01046"></a><span class="lineno"> 1046</span><span class="comment">   * to parameterize Atomic_raw_sev into a template.  It&#39;s a tiny bit cheesy to avoid the latter just to keep the code</span></div>
<div class="line"><a id="l01047" name="l01047"></a><span class="lineno"> 1047</span><span class="comment">   * briefer, but probably well within reasonableness.)</span></div>
<div class="line"><a id="l01048" name="l01048"></a><span class="lineno"> 1048</span><span class="comment">   */</span></div>
<div class="line"><a id="l01049" name="l01049"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a409818a2192ee2544b442b2ea957a76c"> 1049</a></span>  <a class="code hl_class" href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html">Atomic_raw_sev</a> <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a409818a2192ee2544b442b2ea957a76c">m_verbosity_default</a>;</div>
<div class="line"><a id="l01050" name="l01050"></a><span class="lineno"> 1050</span><span class="comment"></span> </div>
<div class="line"><a id="l01051" name="l01051"></a><span class="lineno"> 1051</span><span class="comment">  /**</span></div>
<div class="line"><a id="l01052" name="l01052"></a><span class="lineno"> 1052</span><span class="comment">   * Maps from flat union component index to most verbose (highest) log::Sev for which output_whether_should_log() will</span></div>
<div class="line"><a id="l01053" name="l01053"></a><span class="lineno"> 1053</span><span class="comment">   * return true, when the input component is not null and maps to that flat union index via component_to_union_idx().</span></div>
<div class="line"><a id="l01054" name="l01054"></a><span class="lineno"> 1054</span><span class="comment">   * First, read doc header for Component_union_idx_to_sev_map which described why and how the data structure works</span></div>
<div class="line"><a id="l01055" name="l01055"></a><span class="lineno"> 1055</span><span class="comment">   * as a map; then return here.</span></div>
<div class="line"><a id="l01056" name="l01056"></a><span class="lineno"> 1056</span><span class="comment">   *</span></div>
<div class="line"><a id="l01057" name="l01057"></a><span class="lineno"> 1057</span><span class="comment">   * Semantics are as follows:</span></div>
<div class="line"><a id="l01058" name="l01058"></a><span class="lineno"> 1058</span><span class="comment">   *   - If `m_verbosities_by_component[X]` equals -1 cast appropriately, then that component</span></div>
<div class="line"><a id="l01059" name="l01059"></a><span class="lineno"> 1059</span><span class="comment">   *     key is *not* in the conceptual map (`map::find()` would return `end()`).  This means no verbosity is configured</span></div>
<div class="line"><a id="l01060" name="l01060"></a><span class="lineno"> 1060</span><span class="comment">   *     for that individual component; note this is common-place in practice.  One should then fall back to</span></div>
<div class="line"><a id="l01061" name="l01061"></a><span class="lineno"> 1061</span><span class="comment">   *     #m_verbosity_default.</span></div>
<div class="line"><a id="l01062" name="l01062"></a><span class="lineno"> 1062</span><span class="comment">   *   - If `m_verbosities_by_component[X]` is out of range, same thing.  However, that means they didn&#39;t properly</span></div>
<div class="line"><a id="l01063" name="l01063"></a><span class="lineno"> 1063</span><span class="comment">   *     call init_component_to_union_idx_mapping() to allow for `X`.  Nevertheless, that is allowed when *reading*</span></div>
<div class="line"><a id="l01064" name="l01064"></a><span class="lineno"> 1064</span><span class="comment">   *     (in output_whether_should_log()) to avoid crashing for no great reason.  It is however not allowed</span></div>
<div class="line"><a id="l01065" name="l01065"></a><span class="lineno"> 1065</span><span class="comment">   *     when *writing* (in `configure_*_verbosity()`), so they&#39;d better get it right at that level.</span></div>
<div class="line"><a id="l01066" name="l01066"></a><span class="lineno"> 1066</span><span class="comment">   *     The idea is to be permissive at log call sites, which should not care about ANY of this and just want to</span></div>
<div class="line"><a id="l01067" name="l01067"></a><span class="lineno"> 1067</span><span class="comment">   *     log with their component in peace; but not-permissive when configuring the log system, done at the program</span></div>
<div class="line"><a id="l01068" name="l01068"></a><span class="lineno"> 1068</span><span class="comment">   *     driver level.</span></div>
<div class="line"><a id="l01069" name="l01069"></a><span class="lineno"> 1069</span><span class="comment">   *   - If `m_verbosities_by_component[X]` is in range and not -1, then that value cast to log::Sev is the verbosity</span></div>
<div class="line"><a id="l01070" name="l01070"></a><span class="lineno"> 1070</span><span class="comment">   *     for that individual component.  (In particular, Sev::S_NONE which happens to be 0, means all logging is</span></div>
<div class="line"><a id="l01071" name="l01071"></a><span class="lineno"> 1071</span><span class="comment">   *     disabled for that component.)</span></div>
<div class="line"><a id="l01072" name="l01072"></a><span class="lineno"> 1072</span><span class="comment">   *</span></div>
<div class="line"><a id="l01073" name="l01073"></a><span class="lineno"> 1073</span><span class="comment">   * Note that some log systems will choose to not even allow any elements in #m_verbosities_by_component and leave</span></div>
<div class="line"><a id="l01074" name="l01074"></a><span class="lineno"> 1074</span><span class="comment">   * the config to #m_verbosity_default exclusively; in this case `m_verbosities_by_component` is filled with</span></div>
<div class="line"><a id="l01075" name="l01075"></a><span class="lineno"> 1075</span><span class="comment">   * -1 copies (or might even be empty, if they had never configured any components for whatever reason; by above</span></div>
<div class="line"><a id="l01076" name="l01076"></a><span class="lineno"> 1076</span><span class="comment">   * semantics those have identical meanings).</span></div>
<div class="line"><a id="l01077" name="l01077"></a><span class="lineno"> 1077</span><span class="comment">   */</span></div>
<div class="line"><a id="l01078" name="l01078"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a6b6b4511883c815e81f6427909ed829f"> 1078</a></span>  <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#a3c5c7d62daba9625b0309b31da287585">Component_union_idx_to_sev_map</a> <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a6b6b4511883c815e81f6427909ed829f">m_verbosities_by_component</a>;</div>
<div class="line"><a id="l01079" name="l01079"></a><span class="lineno"> 1079</span><span class="comment"></span> </div>
<div class="line"><a id="l01080" name="l01080"></a><span class="lineno"> 1080</span><span class="comment">  /**</span></div>
<div class="line"><a id="l01081" name="l01081"></a><span class="lineno"> 1081</span><span class="comment">   * Maps each flat union component index to its *output* component name as registered in init_component_names().</span></div>
<div class="line"><a id="l01082" name="l01082"></a><span class="lineno"> 1082</span><span class="comment">   * Note that a given index not being present in this map doesn&#39;t mean it&#39;s not a real component; but</span></div>
<div class="line"><a id="l01083" name="l01083"></a><span class="lineno"> 1083</span><span class="comment">   * init_component_names() caller may have intentionally not supplied it a forward-lookup name, so that instead</span></div>
<div class="line"><a id="l01084" name="l01084"></a><span class="lineno"> 1084</span><span class="comment">   * the number itself would be output.</span></div>
<div class="line"><a id="l01085" name="l01085"></a><span class="lineno"> 1085</span><span class="comment">   *</span></div>
<div class="line"><a id="l01086" name="l01086"></a><span class="lineno"> 1086</span><span class="comment">   * @see init_component_names()</span></div>
<div class="line"><a id="l01087" name="l01087"></a><span class="lineno"> 1087</span><span class="comment">   */</span></div>
<div class="line"><a id="l01088" name="l01088"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a35cb8f5805d2093d13625a528d78919c"> 1088</a></span>  <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#a663307a81245b621e12680d3a4d83df2">Component_union_idx_to_name_map</a> <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a35cb8f5805d2093d13625a528d78919c">m_component_names_by_union_idx</a>;</div>
<div class="line"><a id="l01089" name="l01089"></a><span class="lineno"> 1089</span><span class="comment"></span> </div>
<div class="line"><a id="l01090" name="l01090"></a><span class="lineno"> 1090</span><span class="comment">  /**</span></div>
<div class="line"><a id="l01091" name="l01091"></a><span class="lineno"> 1091</span><span class="comment">   * Maps each distinct component name as registered in init_component_names() to its flat union component index.</span></div>
<div class="line"><a id="l01092" name="l01092"></a><span class="lineno"> 1092</span><span class="comment">   *</span></div>
<div class="line"><a id="l01093" name="l01093"></a><span class="lineno"> 1093</span><span class="comment">   * @see init_component_names()</span></div>
<div class="line"><a id="l01094" name="l01094"></a><span class="lineno"> 1094</span><span class="comment">   */</span></div>
<div class="line"><a id="l01095" name="l01095"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#ad9decea94f2d3297a2b24bc6de7c4657"> 1095</a></span>  <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aa1ed54fc7cef5b0ba4eadf97daf79be7">Component_name_to_union_idx_map</a> <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#ad9decea94f2d3297a2b24bc6de7c4657">m_component_union_idxs_by_name</a>;</div>
<div class="line"><a id="l01096" name="l01096"></a><span class="lineno"> 1096</span>}; <span class="comment">// class Config</span></div>
<div class="line"><a id="l01097" name="l01097"></a><span class="lineno"> 1097</span> </div>
<div class="line"><a id="l01098" name="l01098"></a><span class="lineno"> 1098</span><span class="comment">// Template implementations.</span></div>
<div class="line"><a id="l01099" name="l01099"></a><span class="lineno"> 1099</span> </div>
<div class="line"><a id="l01100" name="l01100"></a><span class="lineno"> 1100</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l01101" name="l01101"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a9b7ba819538d221f190e044cfa6220db"> 1101</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a9b7ba819538d221f190e044cfa6220db">Config::init_component_to_union_idx_mapping</a>(<a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a> enum_to_num_offset,</div>
<div class="line"><a id="l01102" name="l01102"></a><span class="lineno"> 1102</span>                                                 <span class="keywordtype">size_t</span> enum_sparse_length,</div>
<div class="line"><a id="l01103" name="l01103"></a><span class="lineno"> 1103</span>                                                 <span class="keywordtype">bool</span> component_payload_type_info_ptr_is_uniq)</div>
<div class="line"><a id="l01104" name="l01104"></a><span class="lineno"> 1104</span>{</div>
<div class="line"><a id="l01105" name="l01105"></a><span class="lineno"> 1105</span>  assert(enum_sparse_length &gt;= 1);</div>
<div class="line"><a id="l01106" name="l01106"></a><span class="lineno"> 1106</span> </div>
<div class="line"><a id="l01107" name="l01107"></a><span class="lineno"> 1107</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a> component_union_idx_max = enum_to_num_offset + enum_sparse_length - 1;</div>
<div class="line"><a id="l01108" name="l01108"></a><span class="lineno"> 1108</span>  assert(component_union_idx_max &gt;= enum_to_num_offset);</div>
<div class="line"><a id="l01109" name="l01109"></a><span class="lineno"> 1109</span>  assert(component_union_idx_max &gt;= enum_sparse_length);</div>
<div class="line"><a id="l01110" name="l01110"></a><span class="lineno"> 1110</span> </div>
<div class="line"><a id="l01111" name="l01111"></a><span class="lineno"> 1111</span>  <span class="comment">/* typeid(Component_payload) (arg 1) would equal Component(C).payload_type(), where C is a value of type</span></div>
<div class="line"><a id="l01112" name="l01112"></a><span class="lineno"> 1112</span><span class="comment">   * Component_payload.  That is how this mapping would be used subsequently after this call.  Component(C) is</span></div>
<div class="line"><a id="l01113" name="l01113"></a><span class="lineno"> 1113</span><span class="comment">   * routinely provided at log call sites. */</span></div>
<div class="line"><a id="l01114" name="l01114"></a><span class="lineno"> 1114</span>  <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#ae447f7751eb63baefb04fdeeeff95fda">m_component_cfgs_by_payload_type</a>.<a class="code hl_function" href="classflow_1_1log_1_1Component__payload__type__dict.html#af0693c5f5fdd2583d03eb285ff8f4ee0">insert</a>(<span class="keyword">typeid</span>(Component_payload),</div>
<div class="line"><a id="l01115" name="l01115"></a><span class="lineno"> 1115</span>                                          { enum_to_num_offset },</div>
<div class="line"><a id="l01116" name="l01116"></a><span class="lineno"> 1116</span>                                          component_payload_type_info_ptr_is_uniq);</div>
<div class="line"><a id="l01117" name="l01117"></a><span class="lineno"> 1117</span>  <span class="comment">/* ^-- (It&#39;s not necessarily bad to replace an existing per-Component_paylod-offset.  However in doc header behavior</span></div>
<div class="line"><a id="l01118" name="l01118"></a><span class="lineno"> 1118</span><span class="comment">   * is undefined, as it requires looking into the various implications -- not currently worth it.  So for now</span></div>
<div class="line"><a id="l01119" name="l01119"></a><span class="lineno"> 1119</span><span class="comment">   * the above is officially undefined (and may trip assert).) */</span></div>
<div class="line"><a id="l01120" name="l01120"></a><span class="lineno"> 1120</span> </div>
<div class="line"><a id="l01121" name="l01121"></a><span class="lineno"> 1121</span>  <span class="comment">/* Finally make the per-component verbosities table able to hold all keys component_to_union_idx(C) could ever</span></div>
<div class="line"><a id="l01122" name="l01122"></a><span class="lineno"> 1122</span><span class="comment">   * return when C.payload_type() == typeid(Component_payload).  See doc header for</span></div>
<div class="line"><a id="l01123" name="l01123"></a><span class="lineno"> 1123</span><span class="comment">   * m_verbosities_by_component then come back here. */</span></div>
<div class="line"><a id="l01124" name="l01124"></a><span class="lineno"> 1124</span>  <span class="keywordflow">if</span> (component_union_idx_max &gt;= <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a6b6b4511883c815e81f6427909ed829f">m_verbosities_by_component</a>.size())</div>
<div class="line"><a id="l01125" name="l01125"></a><span class="lineno"> 1125</span>  {</div>
<div class="line"><a id="l01126" name="l01126"></a><span class="lineno"> 1126</span>    <span class="comment">/* Every single element starts at -1 which means &quot;not in the conceptual map.&quot;  Note this resize() is the only way</span></div>
<div class="line"><a id="l01127" name="l01127"></a><span class="lineno"> 1127</span><span class="comment">     * elements are added to the vector.  After this it&#39;s all atomic&lt;&gt;::store() to existing elements and</span></div>
<div class="line"><a id="l01128" name="l01128"></a><span class="lineno"> 1128</span><span class="comment">     * atomic&lt;&gt;::load()s from there.</span></div>
<div class="line"><a id="l01129" name="l01129"></a><span class="lineno"> 1129</span><span class="comment">     * (Note: OK, technically there&#39;s another way m_verbosities_by_component is set, in the copy ctor.  See copy ctor&#39;s</span></div>
<div class="line"><a id="l01130" name="l01130"></a><span class="lineno"> 1130</span><span class="comment">     * doc header.)</span></div>
<div class="line"><a id="l01131" name="l01131"></a><span class="lineno"> 1131</span><span class="comment">     * (Note: This requires copying of a Atomic_raw_sev(raw_sev_t(-1)) N times, where N is the number of elements,</span></div>
<div class="line"><a id="l01132" name="l01132"></a><span class="lineno"> 1132</span><span class="comment">     * if any, added to m_verbosities_by_component.  That&#39;s why Atomic_raw_sev() has a copy ctor unlike the</span></div>
<div class="line"><a id="l01133" name="l01133"></a><span class="lineno"> 1133</span><span class="comment">     * underlying atomic&lt;raw_sev_t&gt;.  Its use can be unsafe, in terms of propagation across threads, as said in the</span></div>
<div class="line"><a id="l01134" name="l01134"></a><span class="lineno"> 1134</span><span class="comment">     * copy ctor&#39;s doc header; but since we do the source construction and N copies in the same thread, per that doc</span></div>
<div class="line"><a id="l01135" name="l01135"></a><span class="lineno"> 1135</span><span class="comment">     * header we are safe.) */</span></div>
<div class="line"><a id="l01136" name="l01136"></a><span class="lineno"> 1136</span>    <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a6b6b4511883c815e81f6427909ed829f">m_verbosities_by_component</a>.resize(component_union_idx_max + 1); <span class="comment">// Implied 2nd arg = Atomic_raw_sev(-1).</span></div>
<div class="line"><a id="l01137" name="l01137"></a><span class="lineno"> 1137</span>  }</div>
<div class="line"><a id="l01138" name="l01138"></a><span class="lineno"> 1138</span>} <span class="comment">// Config::init_component_to_union_idx_mapping()</span></div>
<div class="line"><a id="l01139" name="l01139"></a><span class="lineno"> 1139</span> </div>
<div class="line"><a id="l01140" name="l01140"></a><span class="lineno"> 1140</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l01141" name="l01141"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a146a60d96256dbaed4f5f0e7dcd8f529"> 1141</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a146a60d96256dbaed4f5f0e7dcd8f529">Config::init_component_names</a></div>
<div class="line"><a id="l01142" name="l01142"></a><span class="lineno"> 1142</span>       (<span class="keyword">const</span> boost::unordered_multimap&lt;Component_payload, std::string&gt;&amp; component_names,</div>
<div class="line"><a id="l01143" name="l01143"></a><span class="lineno"> 1143</span>        <span class="keywordtype">bool</span> output_components_numerically,</div>
<div class="line"><a id="l01144" name="l01144"></a><span class="lineno"> 1144</span>        <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> payload_type_prefix_or_empty)</div>
<div class="line"><a id="l01145" name="l01145"></a><span class="lineno"> 1145</span>{</div>
<div class="line"><a id="l01146" name="l01146"></a><span class="lineno"> 1146</span>  <span class="keyword">using </span>std::string;</div>
<div class="line"><a id="l01147" name="l01147"></a><span class="lineno"> 1147</span> </div>
<div class="line"><a id="l01148" name="l01148"></a><span class="lineno"> 1148</span>  <span class="comment">/* There is much subtle (not super-exciting) stuff going on below.  It helps to read the contract of the function</span></div>
<div class="line"><a id="l01149" name="l01149"></a><span class="lineno"> 1149</span><span class="comment">   * in some detail; see doc header first, then continue here. */</span></div>
<div class="line"><a id="l01150" name="l01150"></a><span class="lineno"> 1150</span> </div>
<div class="line"><a id="l01151" name="l01151"></a><span class="lineno"> 1151</span>  <span class="comment">/* Assuming for each distinct init_component_names() call they provide a distinct, non-empty one of these, it</span></div>
<div class="line"><a id="l01152" name="l01152"></a><span class="lineno"> 1152</span><span class="comment">   * guarantees no 2 equal component names from different invocations ever ultimately collide.  In other words</span></div>
<div class="line"><a id="l01153" name="l01153"></a><span class="lineno"> 1153</span><span class="comment">   * it&#39;s a poor man&#39;s namespace. */</span></div>
<div class="line"><a id="l01154" name="l01154"></a><span class="lineno"> 1154</span>  <span class="keyword">const</span> <span class="keywordtype">string</span> payload_type_prefix_normalized{<a class="code hl_function" href="classflow_1_1log_1_1Config.html#a428c0ae690c951c1667e24afb6ef43de">normalized_component_name</a>(payload_type_prefix_or_empty)};</div>
<div class="line"><a id="l01155" name="l01155"></a><span class="lineno"> 1155</span> </div>
<div class="line"><a id="l01156" name="l01156"></a><span class="lineno"> 1156</span>  <span class="comment">/* This looks straigtforward, but there&#39;s a surprisingly weird subtlety.  The doc header talks about it:</span></div>
<div class="line"><a id="l01157" name="l01157"></a><span class="lineno"> 1157</span><span class="comment">   * component_names is a multi-map (meaning this iteration might yield the same enum_val 2+ times in a row).</span></div>
<div class="line"><a id="l01158" name="l01158"></a><span class="lineno"> 1158</span><span class="comment">   * This is best explained by example.  This is an explicitly legal component enum fragment:</span></div>
<div class="line"><a id="l01159" name="l01159"></a><span class="lineno"> 1159</span><span class="comment">   *   S_COOL_ENGINE = 5,</span></div>
<div class="line"><a id="l01160" name="l01160"></a><span class="lineno"> 1160</span><span class="comment">   *   S_ENGINE_ALIAS1 = 5,</span></div>
<div class="line"><a id="l01161" name="l01161"></a><span class="lineno"> 1161</span><span class="comment">   *   S_ENGINE_ALIAS2 = 5,</span></div>
<div class="line"><a id="l01162" name="l01162"></a><span class="lineno"> 1162</span><span class="comment">   *</span></div>
<div class="line"><a id="l01163" name="l01163"></a><span class="lineno"> 1163</span><span class="comment">   * Moreover, the typically-auto-generated-via-#macro index-to-name map fragment will be as follows:</span></div>
<div class="line"><a id="l01164" name="l01164"></a><span class="lineno"> 1164</span><span class="comment">   *   S_COOL_ENGINE -&gt; &quot;COOL_ENGINE&quot;</span></div>
<div class="line"><a id="l01165" name="l01165"></a><span class="lineno"> 1165</span><span class="comment">   *   S_ENGINE_ALIAS1 -&gt; &quot;ENGINE_ALIAS1&quot;</span></div>
<div class="line"><a id="l01166" name="l01166"></a><span class="lineno"> 1166</span><span class="comment">   *   S_ENGINE_ALIAS2 -&gt; &quot;ENGINE_ALIAS2&quot;</span></div>
<div class="line"><a id="l01167" name="l01167"></a><span class="lineno"> 1167</span><span class="comment">   *</span></div>
<div class="line"><a id="l01168" name="l01168"></a><span class="lineno"> 1168</span><span class="comment">   * Looks fine, right?  But, when indexing by enum class values, all three S_* keys cited are equal!  They all,</span></div>
<div class="line"><a id="l01169" name="l01169"></a><span class="lineno"> 1169</span><span class="comment">   * really, equal 5.  So a non-multi-map would not be able to even store that mapping; one of the 3 names would</span></div>
<div class="line"><a id="l01170" name="l01170"></a><span class="lineno"> 1170</span><span class="comment">   * &quot;win,&quot; the others being forgotten entirely.  So it&#39;s a multi-map.  So now what?  To be continued inside</span></div>
<div class="line"><a id="l01171" name="l01171"></a><span class="lineno"> 1171</span><span class="comment">   * the loop. */</span></div>
<div class="line"><a id="l01172" name="l01172"></a><span class="lineno"> 1172</span>  <span class="keywordflow">for</span> (<span class="keyword">auto</span> <span class="keyword">const</span> &amp; enum_val_and_name : component_names)</div>
<div class="line"><a id="l01173" name="l01173"></a><span class="lineno"> 1173</span>  {</div>
<div class="line"><a id="l01174" name="l01174"></a><span class="lineno"> 1174</span>    <span class="keyword">const</span> Component_payload enum_val = enum_val_and_name.first;</div>
<div class="line"><a id="l01175" name="l01175"></a><span class="lineno"> 1175</span> </div>
<div class="line"><a id="l01176" name="l01176"></a><span class="lineno"> 1176</span>    <span class="keyword">auto</span> name_sans_prefix_normalized = enum_val_and_name.second;</div>
<div class="line"><a id="l01177" name="l01177"></a><span class="lineno"> 1177</span>    assert(!name_sans_prefix_normalized.empty()); <span class="comment">// Advertised as not allowed.  Implications would be too weird.</span></div>
<div class="line"><a id="l01178" name="l01178"></a><span class="lineno"> 1178</span>    <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a2a7be5337621d131ef084ba69ad95f1b">normalize_component_name</a>(&amp;name_sans_prefix_normalized);</div>
<div class="line"><a id="l01179" name="l01179"></a><span class="lineno"> 1179</span> </div>
<div class="line"><a id="l01180" name="l01180"></a><span class="lineno"> 1180</span>    <span class="keywordtype">string</span> name_normalized;</div>
<div class="line"><a id="l01181" name="l01181"></a><span class="lineno"> 1181</span>    name_normalized.reserve(payload_type_prefix_normalized.size() + name_sans_prefix_normalized.size());</div>
<div class="line"><a id="l01182" name="l01182"></a><span class="lineno"> 1182</span>    name_normalized += payload_type_prefix_normalized;</div>
<div class="line"><a id="l01183" name="l01183"></a><span class="lineno"> 1183</span>    name_normalized += name_sans_prefix_normalized;</div>
<div class="line"><a id="l01184" name="l01184"></a><span class="lineno"> 1184</span> </div>
<div class="line"><a id="l01185" name="l01185"></a><span class="lineno"> 1185</span>    <span class="keyword">auto</span> <span class="keyword">const</span> component_union_idx = <a class="code hl_function" href="classflow_1_1log_1_1Config.html#af2d963a6e1e9e0fc5809764d5718e938">component_to_union_idx</a>(<a class="code hl_class" href="classflow_1_1log_1_1Component.html">Component</a>{enum_val});</div>
<div class="line"><a id="l01186" name="l01186"></a><span class="lineno"> 1186</span> </div>
<div class="line"><a id="l01187" name="l01187"></a><span class="lineno"> 1187</span>    <span class="comment">// Presumably they didn&#39;t call init_component_to_union_idx_mapping&lt;Component_payload&gt;() yet, if this trips.</span></div>
<div class="line"><a id="l01188" name="l01188"></a><span class="lineno"> 1188</span>    assert(component_union_idx != <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a>(-1));</div>
<div class="line"><a id="l01189" name="l01189"></a><span class="lineno"> 1189</span>    <span class="comment">// If this trips, they have allowed a name collision (behavior undefined, as promised).</span></div>
<div class="line"><a id="l01190" name="l01190"></a><span class="lineno"> 1190</span>    assert(!<a class="code hl_function" href="namespaceflow_1_1util.html#a03984e29450abf9cf287c501d6c8f866">util::key_exists</a>(<a class="code hl_variable" href="classflow_1_1log_1_1Config.html#ad9decea94f2d3297a2b24bc6de7c4657">m_component_union_idxs_by_name</a>, name_normalized));</div>
<div class="line"><a id="l01191" name="l01191"></a><span class="lineno"> 1191</span> </div>
<div class="line"><a id="l01192" name="l01192"></a><span class="lineno"> 1192</span>    <span class="comment">// Set up reverse lookup (for verbosity setting by name, at least).</span></div>
<div class="line"><a id="l01193" name="l01193"></a><span class="lineno"> 1193</span>    <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#ad9decea94f2d3297a2b24bc6de7c4657">m_component_union_idxs_by_name</a>[name_normalized] = component_union_idx;</div>
<div class="line"><a id="l01194" name="l01194"></a><span class="lineno"> 1194</span>    <span class="comment">/* Ready!  Let&#39;s analyze the multi-key corner case mentioned before, by example.  This will, across 3 iterations,</span></div>
<div class="line"><a id="l01195" name="l01195"></a><span class="lineno"> 1195</span><span class="comment">     * result in the appropriate mappings:</span></div>
<div class="line"><a id="l01196" name="l01196"></a><span class="lineno"> 1196</span><span class="comment">     *   &quot;COOL_ENGINE&quot; -&gt; component_to_union_idx(S_COOL_ENGINE) -&gt; X</span></div>
<div class="line"><a id="l01197" name="l01197"></a><span class="lineno"> 1197</span><span class="comment">     *   &quot;ENGINE_ALIAS1&quot; -&gt; component_to_union_idx(S_ENGINE_ALIAS1) -&gt; X (same value)</span></div>
<div class="line"><a id="l01198" name="l01198"></a><span class="lineno"> 1198</span><span class="comment">     *   &quot;ENGINE_ALIAS2&quot; -&gt; component_to_union_idx(S_ENGINE_ALIAS2) -&gt; X (same value)</span></div>
<div class="line"><a id="l01199" name="l01199"></a><span class="lineno"> 1199</span><span class="comment">     * This is the advertised behavior.  For config purposes, any of the 3 names linked with 1 enum numerical value</span></div>
<div class="line"><a id="l01200" name="l01200"></a><span class="lineno"> 1200</span><span class="comment">     * refer to the same knob. */</span></div>
<div class="line"><a id="l01201" name="l01201"></a><span class="lineno"> 1201</span> </div>
<div class="line"><a id="l01202" name="l01202"></a><span class="lineno"> 1202</span>    <span class="comment">// Set up forward lookup (for component -&gt; string output, at least).  They can choose to turn this off.</span></div>
<div class="line"><a id="l01203" name="l01203"></a><span class="lineno"> 1203</span>    <span class="keywordflow">if</span> (!output_components_numerically)</div>
<div class="line"><a id="l01204" name="l01204"></a><span class="lineno"> 1204</span>    {</div>
<div class="line"><a id="l01205" name="l01205"></a><span class="lineno"> 1205</span>      <span class="keywordtype">string</span>&amp; output_name_so_far = <a class="code hl_variable" href="classflow_1_1log_1_1Config.html#a35cb8f5805d2093d13625a528d78919c">m_component_names_by_union_idx</a>[component_union_idx];</div>
<div class="line"><a id="l01206" name="l01206"></a><span class="lineno"> 1206</span>      <span class="keywordflow">if</span> (output_name_so_far.empty())</div>
<div class="line"><a id="l01207" name="l01207"></a><span class="lineno"> 1207</span>      {</div>
<div class="line"><a id="l01208" name="l01208"></a><span class="lineno"> 1208</span>        assert(!name_normalized.empty());</div>
<div class="line"><a id="l01209" name="l01209"></a><span class="lineno"> 1209</span>        output_name_so_far = std::move(name_normalized);</div>
<div class="line"><a id="l01210" name="l01210"></a><span class="lineno"> 1210</span>      }</div>
<div class="line"><a id="l01211" name="l01211"></a><span class="lineno"> 1211</span>      <span class="keywordflow">else</span></div>
<div class="line"><a id="l01212" name="l01212"></a><span class="lineno"> 1212</span>      {</div>
<div class="line"><a id="l01213" name="l01213"></a><span class="lineno"> 1213</span>        assert(!name_sans_prefix_normalized.empty());</div>
<div class="line"><a id="l01214" name="l01214"></a><span class="lineno"> 1214</span>        output_name_so_far += <span class="charliteral">&#39;,&#39;</span>;</div>
<div class="line"><a id="l01215" name="l01215"></a><span class="lineno"> 1215</span>        output_name_so_far += name_sans_prefix_normalized;</div>
<div class="line"><a id="l01216" name="l01216"></a><span class="lineno"> 1216</span>      }</div>
<div class="line"><a id="l01217" name="l01217"></a><span class="lineno"> 1217</span>      <span class="comment">/* Ready!  Let&#39;s analyze the multi-key corner case mentioned before, by example.  This will, across 3 iterations,</span></div>
<div class="line"><a id="l01218" name="l01218"></a><span class="lineno"> 1218</span><span class="comment">       * result in the appropriate single mapping:</span></div>
<div class="line"><a id="l01219" name="l01219"></a><span class="lineno"> 1219</span><span class="comment">       *   X -&gt; &quot;&lt;prefix&gt;COOL_ENGINE,ENGINE_ALIAS1,ENGINE_ALIAS2&quot;</span></div>
<div class="line"><a id="l01220" name="l01220"></a><span class="lineno"> 1220</span><span class="comment">       * where X == component_to_union_idx(S_COOL_ENGINE == S_ENGINE_ALIAS1 == S_ENGINE_ALIAS2).</span></div>
<div class="line"><a id="l01221" name="l01221"></a><span class="lineno"> 1221</span><span class="comment">       * This is the advertised behavior.  For output purposes, any of the enum values linked with 1 enum num value</span></div>
<div class="line"><a id="l01222" name="l01222"></a><span class="lineno"> 1222</span><span class="comment">       * refer to the same component name which contains all 3 individual strings comma-joined. */</span></div>
<div class="line"><a id="l01223" name="l01223"></a><span class="lineno"> 1223</span>    }</div>
<div class="line"><a id="l01224" name="l01224"></a><span class="lineno"> 1224</span>  } <span class="comment">// for (enum_val_and_name : component_names)</span></div>
<div class="line"><a id="l01225" name="l01225"></a><span class="lineno"> 1225</span>} <span class="comment">// Config::init_component_names()</span></div>
<div class="line"><a id="l01226" name="l01226"></a><span class="lineno"> 1226</span> </div>
<div class="line"><a id="l01227" name="l01227"></a><span class="lineno"> 1227</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l01228" name="l01228"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#adfde40890c0dc1fa8956451f44251dc8"> 1228</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#adfde40890c0dc1fa8956451f44251dc8">Config::configure_component_verbosity</a>(<a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> most_verbose_sev, Component_payload component_payload)</div>
<div class="line"><a id="l01229" name="l01229"></a><span class="lineno"> 1229</span>{</div>
<div class="line"><a id="l01230" name="l01230"></a><span class="lineno"> 1230</span>  <span class="keyword">const</span> <span class="keyword">auto</span> component_union_idx = <a class="code hl_function" href="classflow_1_1log_1_1Config.html#af2d963a6e1e9e0fc5809764d5718e938">component_to_union_idx</a>(<a class="code hl_class" href="classflow_1_1log_1_1Component.html">Component</a>{component_payload});</div>
<div class="line"><a id="l01231" name="l01231"></a><span class="lineno"> 1231</span>  <span class="keywordflow">if</span> (component_union_idx == <a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">component_union_idx_t</a>(-1))</div>
<div class="line"><a id="l01232" name="l01232"></a><span class="lineno"> 1232</span>  {</div>
<div class="line"><a id="l01233" name="l01233"></a><span class="lineno"> 1233</span>    <span class="comment">/* If they called init_component_to_union_idx_mapping&lt;Component_payload&gt;(), this cannot happen.</span></div>
<div class="line"><a id="l01234" name="l01234"></a><span class="lineno"> 1234</span><span class="comment">     * If they did not, then this is the advertised behavior, but probably they&#39;re doing something wrong. */</span></div>
<div class="line"><a id="l01235" name="l01235"></a><span class="lineno"> 1235</span>    <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a id="l01236" name="l01236"></a><span class="lineno"> 1236</span>  }</div>
<div class="line"><a id="l01237" name="l01237"></a><span class="lineno"> 1237</span>  <span class="comment">// else</span></div>
<div class="line"><a id="l01238" name="l01238"></a><span class="lineno"> 1238</span> </div>
<div class="line"><a id="l01239" name="l01239"></a><span class="lineno"> 1239</span>  <a class="code hl_function" href="classflow_1_1log_1_1Config.html#aee6877cec4b070e18a40090f080e76ca">store_severity_by_component</a>(component_union_idx, <span class="keyword">static_cast&lt;</span><a class="code hl_typedef" href="classflow_1_1log_1_1Config.html#acae76e3367bd497f5b00f46e48b3a39c">raw_sev_t</a><span class="keyword">&gt;</span>(most_verbose_sev));</div>
<div class="line"><a id="l01240" name="l01240"></a><span class="lineno"> 1240</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a id="l01241" name="l01241"></a><span class="lineno"> 1241</span>} <span class="comment">// Config::configure_component_verbosity()</span></div>
<div class="line"><a id="l01242" name="l01242"></a><span class="lineno"> 1242</span> </div>
<div class="line"><a id="l01243" name="l01243"></a><span class="lineno"> 1243</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Component_payload&gt;</div>
<div class="line"><a id="l01244" name="l01244"></a><span class="lineno"><a class="line" href="classflow_1_1log_1_1Config.html#a12f1147ae51ee6f9645dcd46e67c8410"> 1244</a></span><span class="keywordtype">size_t</span> <a class="code hl_function" href="classflow_1_1log_1_1Config.html#a12f1147ae51ee6f9645dcd46e67c8410">Config::standard_component_payload_enum_sparse_length</a>() <span class="comment">// Static.</span></div>
<div class="line"><a id="l01245" name="l01245"></a><span class="lineno"> 1245</span>{</div>
<div class="line"><a id="l01246" name="l01246"></a><span class="lineno"> 1246</span>  <span class="keywordflow">return</span> <span class="keyword">static_cast&lt;</span><span class="keywordtype">size_t</span><span class="keyword">&gt;</span>(Component_payload::S_END_SENTINEL);</div>
<div class="line"><a id="l01247" name="l01247"></a><span class="lineno"> 1247</span>  <span class="comment">/* To reiterate, if one just plops S_END_SENTINEL at the end of an `enum class` -- with no manually assigned value --</span></div>
<div class="line"><a id="l01248" name="l01248"></a><span class="lineno"> 1248</span><span class="comment">   * its value will be correct for our purposes.  That does assume, though, that the immediately preceding member</span></div>
<div class="line"><a id="l01249" name="l01249"></a><span class="lineno"> 1249</span><span class="comment">   * has otherwise the highest numeric value (which is the case if, but not only if, one lists them in numeric order</span></div>
<div class="line"><a id="l01250" name="l01250"></a><span class="lineno"> 1250</span><span class="comment">   * as opposed to out of order).  Additionally that assumes, essentially, its backing type is unsigned and no bigger</span></div>
<div class="line"><a id="l01251" name="l01251"></a><span class="lineno"> 1251</span><span class="comment">   * than our return type size_t.  (A tigher, less restrictive requirement could be written out, but this isn&#39;t a</span></div>
<div class="line"><a id="l01252" name="l01252"></a><span class="lineno"> 1252</span><span class="comment">   * math proof over here.)  In particular: Certainly all of these things are guaranteed if one uses</span></div>
<div class="line"><a id="l01253" name="l01253"></a><span class="lineno"> 1253</span><span class="comment">   * config_enum_start_hpp.macros.hpp, as documented therein, to create Component_payload. */</span></div>
<div class="line"><a id="l01254" name="l01254"></a><span class="lineno"> 1254</span>}</div>
<div class="line"><a id="l01255" name="l01255"></a><span class="lineno"> 1255</span> </div>
<div class="line"><a id="l01256" name="l01256"></a><span class="lineno"> 1256</span>} <span class="comment">// namespace flow::log</span></div>
<div class="ttc" id="aclassflow_1_1log_1_1Component__payload__type__dict_html"><div class="ttname"><a href="classflow_1_1log_1_1Component__payload__type__dict.html">flow::log::Component_payload_type_dict&lt; value_for_exposition&lt; Component_config &gt;, value_for_exposition&lt; Component_config &gt; &gt;</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Component__payload__type__dict_html_af0693c5f5fdd2583d03eb285ff8f4ee0"><div class="ttname"><a href="classflow_1_1log_1_1Component__payload__type__dict.html#af0693c5f5fdd2583d03eb285ff8f4ee0">flow::log::Component_payload_type_dict::insert</a></div><div class="ttdeci">void insert(const std::type_info &amp;type, Cfg cfg, bool type_info_ptr_is_uniq)</div><div class="ttdoc">Adds a mapping from the given type to a Cfg value, so it can be obtained by lookup().</div><div class="ttdef"><b>Definition:</b> <a href="component__cfg_8hpp_source.html#l00708">component_cfg.hpp:708</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Component_html"><div class="ttname"><a href="classflow_1_1log_1_1Component.html">flow::log::Component</a></div><div class="ttdoc">A light-weight class, each object storing a component payload encoding an enum value from enum type o...</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l00839">log.hpp:840</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Component_html_a287888e2943b312f4febc3e8e130fc80"><div class="ttname"><a href="classflow_1_1log_1_1Component.html#a287888e2943b312f4febc3e8e130fc80">flow::log::Component::enum_raw_t</a></div><div class="ttdeci">unsigned int enum_raw_t</div><div class="ttdoc">The type Payload must be enum class Payload : enum_raw_t: an enum type encoded via this integer type.</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l00845">log.hpp:845</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_1_1Atomic__raw__sev_html"><div class="ttname"><a href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html">flow::log::Config::Atomic_raw_sev</a></div><div class="ttdoc">Trivial wrapper of atomic&lt;raw_sev_t&gt; which adds a couple of things to make it possible to construct,...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00882">config.hpp:883</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_1_1Atomic__raw__sev_html_a0edf54321d64532405b9786dd707e026"><div class="ttname"><a href="classflow_1_1log_1_1Config_1_1Atomic__raw__sev.html#a0edf54321d64532405b9786dd707e026">flow::log::Config::Atomic_raw_sev::Atomic_raw_sev</a></div><div class="ttdeci">Atomic_raw_sev(raw_sev_t init_val=raw_sev_t(-1))</div><div class="ttdoc">Constructs the atomic to the given value, guaranteed to be load()ed as such in all subsequent accesse...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00274">config.cpp:274</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html"><div class="ttname"><a href="classflow_1_1log_1_1Config.html">flow::log::Config</a></div><div class="ttdoc">Class used to configure the filtering and logging behavior of Loggers; its use in your custom Loggers...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00316">config.hpp:317</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a12f1147ae51ee6f9645dcd46e67c8410"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a12f1147ae51ee6f9645dcd46e67c8410">flow::log::Config::standard_component_payload_enum_sparse_length</a></div><div class="ttdeci">static size_t standard_component_payload_enum_sparse_length()</div><div class="ttdoc">Returns highest numeric value in the given component-payload enum, plus 1, assuming that enum was cre...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01244">config.hpp:1244</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a146a60d96256dbaed4f5f0e7dcd8f529"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a146a60d96256dbaed4f5f0e7dcd8f529">flow::log::Config::init_component_names</a></div><div class="ttdeci">void init_component_names(const boost::unordered_multimap&lt; Component_payload, std::string &gt; &amp;component_names, bool output_components_numerically=false, util::String_view payload_type_prefix_or_empty=util::String_view())</div><div class="ttdoc">Registers the string names of each member of the enum class Component_payload earlier registered via ...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01141">config.hpp:1142</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a1b16be31f5dcfba9536a377c9d29abb6"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a1b16be31f5dcfba9536a377c9d29abb6">flow::log::Config::m_use_human_friendly_time_stamps</a></div><div class="ttdeci">bool m_use_human_friendly_time_stamps</div><div class="ttdoc">Config setting: If true, time stamps will include a (deterministically formatted) date,...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00793">config.hpp:793</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a20ba1556441155d7086282f76d051f61"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a20ba1556441155d7086282f76d051f61">flow::log::Config::Config</a></div><div class="ttdeci">Config(Sev most_verbose_sev_default=S_MOST_VERBOSE_SEV_DEFAULT)</div><div class="ttdoc">Constructs a conceptually blank but functional set of Config.</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00031">config.cpp:31</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a2a7be5337621d131ef084ba69ad95f1b"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a2a7be5337621d131ef084ba69ad95f1b">flow::log::Config::normalize_component_name</a></div><div class="ttdeci">static void normalize_component_name(std::string *name)</div><div class="ttdoc">Normalizes given component name in place.</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00249">config.cpp:249</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a2f266ee7e22d1090ab4de76e532cab89"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a2f266ee7e22d1090ab4de76e532cab89">flow::log::Config::configure_component_verbosity_by_name</a></div><div class="ttdeci">bool configure_component_verbosity_by_name(Sev most_verbose_sev, util::String_view component_name)</div><div class="ttdoc">Like configure_component_verbosity(), but the component is to be specified by its registered string n...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00134">config.cpp:134</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a35cb8f5805d2093d13625a528d78919c"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a35cb8f5805d2093d13625a528d78919c">flow::log::Config::m_component_names_by_union_idx</a></div><div class="ttdeci">Component_union_idx_to_name_map m_component_names_by_union_idx</div><div class="ttdoc">Maps each flat union component index to its output component name as registered in init_component_nam...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01088">config.hpp:1088</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a3c5c7d62daba9625b0309b31da287585"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a3c5c7d62daba9625b0309b31da287585">flow::log::Config::Component_union_idx_to_sev_map</a></div><div class="ttdeci">std::vector&lt; Atomic_raw_sev &gt; Component_union_idx_to_sev_map</div><div class="ttdoc">Short-hand for fast-lookup, thread-safe-for-RW mapping from flat-union-component-table index to max a...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00968">config.hpp:968</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a409818a2192ee2544b442b2ea957a76c"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a409818a2192ee2544b442b2ea957a76c">flow::log::Config::m_verbosity_default</a></div><div class="ttdeci">Atomic_raw_sev m_verbosity_default</div><div class="ttdoc">Most verbose (highest) log::Sev for which output_whether_should_log() will return true,...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01049">config.hpp:1049</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a428c0ae690c951c1667e24afb6ef43de"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a428c0ae690c951c1667e24afb6ef43de">flow::log::Config::normalized_component_name</a></div><div class="ttdeci">static std::string normalized_component_name(util::String_view name)</div><div class="ttdoc">Normalized version of given component name.</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00240">config.cpp:240</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a60c9a16ebb764e4fcc4208a55c2e785d"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a60c9a16ebb764e4fcc4208a55c2e785d">flow::log::Config::operator=</a></div><div class="ttdeci">void operator=(const Config &amp;)=delete</div><div class="ttdoc">For now at least there's no reason for copy assignment.</div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a6376bf2af57f655c1cdf00791e6a2f7f"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a6376bf2af57f655c1cdf00791e6a2f7f">flow::log::Config::output_component_to_ostream</a></div><div class="ttdeci">bool output_component_to_ostream(std::ostream *os, const Component &amp;component) const</div><div class="ttdoc">An output of Config, this writes a string representation of the given component value to the given os...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00152">config.cpp:152</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a663307a81245b621e12680d3a4d83df2"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a663307a81245b621e12680d3a4d83df2">flow::log::Config::Component_union_idx_to_name_map</a></div><div class="ttdeci">boost::unordered_map&lt; component_union_idx_t, std::string &gt; Component_union_idx_to_name_map</div><div class="ttdoc">Short-hand for map that is essentially the inverse of Component_name_to_union_idx_map.</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00982">config.hpp:982</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a6b6b4511883c815e81f6427909ed829f"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a6b6b4511883c815e81f6427909ed829f">flow::log::Config::m_verbosities_by_component</a></div><div class="ttdeci">Component_union_idx_to_sev_map m_verbosities_by_component</div><div class="ttdoc">Maps from flat union component index to most verbose (highest) log::Sev for which output_whether_shou...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01078">config.hpp:1078</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a81da2c80d99cdd43c66a0df2eed64c70"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a81da2c80d99cdd43c66a0df2eed64c70">flow::log::Config::this_thread_verbosity_override</a></div><div class="ttdeci">static Sev * this_thread_verbosity_override()</div><div class="ttdoc">Returns pointer to this thread's mutable verbosity override, for querying or assignment alike.</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00257">config.cpp:257</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a94e6c81a4e3dd9b41c1b468f7d7c1a90"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a94e6c81a4e3dd9b41c1b468f7d7c1a90">flow::log::Config::S_MOST_VERBOSE_SEV_DEFAULT</a></div><div class="ttdeci">static const Sev S_MOST_VERBOSE_SEV_DEFAULT</div><div class="ttdoc">Recommended default/catch-all most-verbose-severity value if no specific config is given.</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00330">config.hpp:330</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_a9b7ba819538d221f190e044cfa6220db"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#a9b7ba819538d221f190e044cfa6220db">flow::log::Config::init_component_to_union_idx_mapping</a></div><div class="ttdeci">void init_component_to_union_idx_mapping(component_union_idx_t enum_to_num_offset, size_t enum_sparse_length, bool component_payload_type_info_ptr_is_uniq=false)</div><div class="ttdoc">Registers a generically-typed enum class that represents the full set of the calling module's possibl...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01101">config.hpp:1101</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_aa1ed54fc7cef5b0ba4eadf97daf79be7"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#aa1ed54fc7cef5b0ba4eadf97daf79be7">flow::log::Config::Component_name_to_union_idx_map</a></div><div class="ttdeci">boost::unordered_map&lt; std::string, component_union_idx_t &gt; Component_name_to_union_idx_map</div><div class="ttdoc">Short-hand for fast-lookup map from normalized component name to its flat-union-component-table index...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00979">config.hpp:979</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_aabb6bf7c67b40faeab764ad695b63b9d"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#aabb6bf7c67b40faeab764ad695b63b9d">flow::log::Config::component_union_idx_t</a></div><div class="ttdeci">Component::enum_raw_t component_union_idx_t</div><div class="ttdoc">Unsigned index into the flat union of component tables maintained by a Config, combining potentially ...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00325">config.hpp:325</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_ab025990297cc07d51aaec277af203dfe"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#ab025990297cc07d51aaec277af203dfe">flow::log::Config::this_thread_verbosity_override_auto</a></div><div class="ttdeci">static util::Scoped_setter&lt; Sev &gt; this_thread_verbosity_override_auto(Sev most_verbose_sev_or_none)</div><div class="ttdoc">Sets *(this_thread_verbosity_override()) = most_verbose_sev_or_none; and returns an object that shall...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00267">config.cpp:267</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_ab067e9e513530e7484a30f568b1e11d5"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#ab067e9e513530e7484a30f568b1e11d5">flow::log::Config::Config</a></div><div class="ttdeci">Config(Config &amp;&amp;)=delete</div><div class="ttdoc">For now at least there's no reason for move-construction.</div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_ac562cc0132f6cfa81b42c332400033ae"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#ac562cc0132f6cfa81b42c332400033ae">flow::log::Config::configure_default_verbosity</a></div><div class="ttdeci">void configure_default_verbosity(Sev most_verbose_sev_default, bool reset)</div><div class="ttdoc">Sets the default verbosity to the given value, to be used by subsequent output_whether_should_log() c...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00116">config.cpp:116</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_ac8a787b8026d84814bf4edcc91432447"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#ac8a787b8026d84814bf4edcc91432447">flow::log::Config::operator=</a></div><div class="ttdeci">void operator=(Config &amp;&amp;)=delete</div><div class="ttdoc">For now at least there's no reason for move assignment.</div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_acae76e3367bd497f5b00f46e48b3a39c"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#acae76e3367bd497f5b00f46e48b3a39c">flow::log::Config::raw_sev_t</a></div><div class="ttdeci">uint8_t raw_sev_t</div><div class="ttdoc">How we store a log::Sev (a mere enum itself) in a certain data structure.</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00859">config.hpp:859</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_ad9decea94f2d3297a2b24bc6de7c4657"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#ad9decea94f2d3297a2b24bc6de7c4657">flow::log::Config::m_component_union_idxs_by_name</a></div><div class="ttdeci">Component_name_to_union_idx_map m_component_union_idxs_by_name</div><div class="ttdoc">Maps each distinct component name as registered in init_component_names() to its flat union component...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01095">config.hpp:1095</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_add2f471079c285065c692b8e796ad787"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#add2f471079c285065c692b8e796ad787">flow::log::Config::Config</a></div><div class="ttdeci">Config(const Config &amp;src)</div><div class="ttdoc">Copy-constructs *this to be equal to src config object.</div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_adfde40890c0dc1fa8956451f44251dc8"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#adfde40890c0dc1fa8956451f44251dc8">flow::log::Config::configure_component_verbosity</a></div><div class="ttdeci">bool configure_component_verbosity(Sev most_verbose_sev, Component_payload component_payload)</div><div class="ttdoc">Sets the per-component verbosity for the given component to the given value, to be used by subsequent...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01228">config.hpp:1228</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_ae429a329e31a41ba75f94578b0e7f26c"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#ae429a329e31a41ba75f94578b0e7f26c">flow::log::Config::output_whether_should_log</a></div><div class="ttdeci">bool output_whether_should_log(Sev sev, const Component &amp;component) const</div><div class="ttdoc">A key output of Config, this computes the verbosity-filtering answer to Logger::should_log() based on...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00184">config.cpp:184</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_ae447f7751eb63baefb04fdeeeff95fda"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#ae447f7751eb63baefb04fdeeeff95fda">flow::log::Config::m_component_cfgs_by_payload_type</a></div><div class="ttdeci">Component_payload_type_to_cfg_map m_component_cfgs_by_payload_type</div><div class="ttdoc">Fast-lookup map from distinct Component_payload type to the config for that component enum.</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l01034">config.hpp:1034</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_aee6877cec4b070e18a40090f080e76ca"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#aee6877cec4b070e18a40090f080e76ca">flow::log::Config::store_severity_by_component</a></div><div class="ttdeci">void store_severity_by_component(component_union_idx_t component_union_idx, raw_sev_t most_verbose_sev_or_none)</div><div class="ttdoc">Helper that for the given flat-union-component-index saves the given per-component verbosity,...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00062">config.cpp:62</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Config_html_af2d963a6e1e9e0fc5809764d5718e938"><div class="ttname"><a href="classflow_1_1log_1_1Config.html#af2d963a6e1e9e0fc5809764d5718e938">flow::log::Config::component_to_union_idx</a></div><div class="ttdeci">component_union_idx_t component_to_union_idx(const Component &amp;component) const</div><div class="ttdoc">Given a component in the form user provides it at log call sites, returns its index in the flat compo...</div><div class="ttdef"><b>Definition:</b> <a href="config_8cpp_source.html#l00040">config.cpp:40</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Scoped__setter_html"><div class="ttname"><a href="classflow_1_1util_1_1Scoped__setter.html">flow::util::Scoped_setter</a></div><div class="ttdoc">A simple RAII-pattern class template that, at construction, sets the specified location in memory to ...</div><div class="ttdef"><b>Definition:</b> <a href="util_2util_8hpp_source.html#l00144">util.hpp:145</a></div></div>
<div class="ttc" id="acomponent__cfg_8hpp_html"><div class="ttname"><a href="component__cfg_8hpp.html">component_cfg.hpp</a></div></div>
<div class="ttc" id="alog_8hpp_html"><div class="ttname"><a href="log_8hpp.html">log.hpp</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html"><div class="ttname"><a href="namespaceflow_1_1log.html">flow::log</a></div><div class="ttdoc">Flow module providing logging functionality.</div><div class="ttdef"><b>Definition:</b> <a href="async__file__logger_8cpp_source.html#l00027">async_file_logger.cpp:28</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">flow::log::Sev</a></div><div class="ttdeci">Sev</div><div class="ttdoc">Enumeration containing one of several message severity levels, ordered from highest to lowest.</div><div class="ttdef"><b>Definition:</b> <a href="log__fwd_8hpp_source.html#l00223">log_fwd.hpp:224</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_a03984e29450abf9cf287c501d6c8f866"><div class="ttname"><a href="namespaceflow_1_1util.html#a03984e29450abf9cf287c501d6c8f866">flow::util::key_exists</a></div><div class="ttdeci">bool key_exists(const Container &amp;container, const typename Container::key_type &amp;key)</div><div class="ttdoc">Returns true if and only if the given key is present at least once in the given associative container...</div><div class="ttdef"><b>Definition:</b> <a href="util_2util_8hpp_source.html#l00301">util.hpp:301</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_ae4dc52186797094b3040379ff19124c9"><div class="ttname"><a href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">flow::util::String_view</a></div><div class="ttdeci">Basic_string_view&lt; char &gt; String_view</div><div class="ttdoc">Commonly used char-based Basic_string_view. See its doc header.</div><div class="ttdef"><b>Definition:</b> <a href="string__view_8hpp_source.html#l00191">string_view.hpp:191</a></div></div>
<div class="ttc" id="anamespaceflow_html_ae02da22c4a101eaab447511c905e4f32"><div class="ttname"><a href="namespaceflow.html#ae02da22c4a101eaab447511c905e4f32">flow::uint8_t</a></div><div class="ttdeci">unsigned char uint8_t</div><div class="ttdoc">Byte. Best way to represent a byte of binary data. This is 8 bits on all modern systems.</div><div class="ttdef"><b>Definition:</b> <a href="common_8hpp_source.html#l00391">common.hpp:391</a></div></div>
<div class="ttc" id="astructflow_1_1log_1_1Config_1_1Component__config_html"><div class="ttname"><a href="structflow_1_1log_1_1Config_1_1Component__config.html">flow::log::Config::Component_config</a></div><div class="ttdoc">The set of config stored for each distinct (as determined by Component::payload_type(),...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00805">config.hpp:806</a></div></div>
<div class="ttc" id="astructflow_1_1log_1_1Config_1_1Component__config_html_af2e34d559da2d9d28cd744be5f8b6f07"><div class="ttname"><a href="structflow_1_1log_1_1Config_1_1Component__config.html#af2e34d559da2d9d28cd744be5f8b6f07">flow::log::Config::Component_config::m_enum_to_num_offset</a></div><div class="ttdeci">component_union_idx_t m_enum_to_num_offset</div><div class="ttdoc">See the enum_to_num_offset arg in init_component_to_union_idx_mapping() doc header.</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00810">config.hpp:810</a></div></div>
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